Among adults, there is only one legal way to monitor another person's digital activity: with their consent. The word appears in all industry advertising, almost always as a formality. This guide addresses what it means legally, when it is valid, when it is not, and how to create an agreement that works without turning into surveillance.
What is valid consent?
The General Data Protection Law defines consent as a manifestation free, informed and unequivocal. When applied to monitoring between adults, this means four simultaneous requirements:
- Free: Consent given without coercion. Consent obtained under threat of termination, exposure, or loss of access to children is not free—it is coercion.
- Informed: The person knows exactly what will be collected, for how long, and who will see it.
- Unequivocal: It was stated clearly. Silence is not consent, and neither is "he left his cell phone open.".
- Revocable: It can be withdrawn at any time without incurring any penalty.
Without any of the four, it reverts to... Article 154-A of the Penal Code: unauthorized access to a computer system, punishable by imprisonment from 1 to 4 years and a fine.
When consent is not valid.
Obtained under pressure
“"If you have nothing to hide, install it." This phrase perfectly illustrates vitiated consent. Agreement given to end a discussion or avoid an accusation does not fulfill the requirement of freedom.
Signed once, charged forever.
Authorization is not permanent. Those who consented in March can withdraw their consent in April, and from then on, collection is illegal — even if the person had "agreed" beforehand.
Too generic
Authorizing "monitoring" doesn't authorize everything. The scope needs to be specific: location is different from messages, which is different from environment recording.
Given by someone who couldn't give.
Only the account holder can consent to their own device. No one authorizes monitoring by third parties — not a spouse for their spouse, nor one partner for another.
Situations where the agreement makes sense.
Shared location for family
The most common and healthiest scenario. Elderly parents, teenagers arriving home at night, a group traveling. Native sharing of Google Maps and of the Search Apple's agreement is mutual, transparent, and terminable by either party at any time — characteristics that define a legitimate agreement.
Corporate device
The company monitors the device it provides, with a written, signed policy limited to work-related and professional use. The employee's personal device is kept out of reach, even if they use it for work.
Care for a person with special needs
Support for a family member with Alzheimer's or a condition affecting their orientation. Here, the primary concern is usually protecting their life, and ideally, this should be coordinated with the family and, when possible, with the person themselves when they are lucid.
Reciprocity and scope: how to put together the agreement.
If two adults decide to share information, three rules prevent it from turning into a controlling situation:
- Reciprocity. It applies to both sides, with the same data. An agreement in which only one side is considered is not an agreement, it's submission.
- Minimum scope. Share what addresses the real concern and nothing more. Real-time location solves safety on the way home; reading messages solves nothing and creates a new problem.
- Deadline and review. Set a timeframe—one month, three months—and reassess. Surveillance without an end date ceases to be an agreement and becomes a routine of control.
What no agreement can fix.
Let's be clear: when monitoring is proposed to resolve distrust in a relationship, it usually makes the situation worse. The check provides relief for a few minutes, but it returns stronger; jealousy doesn't diminish with data, it feeds on it.
If the root cause is infidelity that has already occurred, couples therapy tends to produce results where tracking does not. If the root cause is control, consensual monitoring may be the formalization of an abusive pattern—and is a sign to seek help, not a tool.
For younger children, the rule is different.
Minors are under parental authority, and supervision is legitimate regardless of consent. Even so, the practical recommendation remains transparency. Google Family Link and the Usage Time iPhone privacy policies are free, visible on the device, and cover screen time, installation approvals, content filtering, and location services.
Google Family Link
AndroidHow to withdraw consent
If you authorized it and then changed your mind, the right to revoke it is yours, and it doesn't depend on negotiation.
- Communicate in a documented way — a written message serves as proof of the date.
- Turn off sharing in the app and revoke permissions in Settings.
- Check it out Accessibility It is Device administrators, where monitoring programs register.
- Change your passwords from another device, starting with your Google or Apple account, which has two-step verification.
- If the collection continues after that, a crime has been committed from the moment of revocation. Keep the evidence and seek legal advice.
In the context of domestic violence, seek support before disconnecting: abrupt withdrawal can escalate the risk. The Women's Helpline provides free assistance by phone. 180.
Frequently Asked Questions
Is verbal consent valid?
It may be legally valid, but it's difficult to prove. A written record protects both sides.
If I authorized it, can I take it back?
Always. Revocation is the right of the holder and cannot be conditional on anything.
Can my partner demand access to my cell phone?
That right does not exist. Marriage does not transfer ownership of the device nor does it remove the confidentiality of communications.
Can a company monitor my personal cell phone?
No. Only the corporate device, with an informed policy and restricted to professional use.
What if the person consented but didn't know the full extent of the problem?
The consent is invalid because it was not provided. The scope needs to be explicit.
In summary
Consent is what separates legitimate surveillance from crime — and it only counts when it is freely given, informed, specific, and revocable. Reciprocal agreements with minimal scope, such as shared family location, work well. Monitoring proposed to cure mistrust doesn't work, even with a signed consent form: the problem has never been a lack of data.
What to do, in order.
- Set a limit per application, not just a total limit. Allowing free study time and restricting short video time works better than a single limit.
- Review the agreement every few months. Limits that don't match age become a source of conflict and challenges.
- Use the official tool. Google Family Link on Android and Screen Time on iPhone: free, visible on the device, and without requiring you to disable any protection.
- Enable installation approval. It prevents new apps from appearing without your knowledge, which is half the problem.
Where most people slip
- Installing hidden software on an adult's cell phone is a crime under article 154-A, punishable by 1 to 4 years imprisonment.
- Disabling Play Protect to install files from outside sources is the most common vector for banking trojans.
- Relying on evidence obtained through unauthorized access in a legal proceeding—it is discarded and exposes whoever produced it.
- Don't believe promises of monitoring based solely on a phone number; it doesn't exist.
The alternative that is already included in the system
To find a lost device, Find My Device and Find My iPhone are free and come standard: they sound an alarm even when the device is on silent, show it on a map, and remotely lock and erase it. It's worth checking today if they are activated — once lost, you can't configure them anymore.
