You are not the police
The job is not to catch anybody out. Your friend set this up themselves, in a calmer hour, precisely so that the decision at eleven at night would not be theirs alone.
So the question is never whether they deserve it. It is whether the version of them who set this up would want you to say yes to this.
A good answer is quick and short
Speed matters more than wording. Somebody is standing there waiting, and a thoughtful reply twenty minutes later is worse for them than a blunt one now.
You do not owe an explanation. Yes is fine on its own. No is fine on its own. A line of why is a kindness, not a requirement.
Saying no is the whole point
A Keyholder who has never said no is not holding anything, and both of you know it.
It is worth saying out loud, once, early: I am going to turn some of these down, that is what you asked me for, and it is not a comment on you. Having said that in advance makes the first no enormously easier for both of you.
- No is a normal answer, not a rebuke.
- You are allowed to grant less than was asked for. Fifteen minutes instead of an hour is a real answer.
- Not answering also has a meaning: it stays blocked. That is safe, but it is not the same as deciding.
When to just say yes
Say yes when the reason is specific and finite. Somebody is picking them up, a friend is expecting a reply, they need to look something up for tomorrow.
Be more careful when the reason is a mood rather than a task. Bored, restless, one quick look. That is the exact request the arrangement was built to sit between, and both of you knew it when you set it up.
What you can and cannot see
You see that they asked, what you answered, and how long they have kept it up. Not which apps, not what times, not what they were doing.
That limit is deliberate. You agreed to hold a key, not to supervise somebody, and an arrangement that hands you a surveillance feed is one they will quietly leave. If you find yourself wanting more detail, the thing to do is ask them, not the app.
Common questions
What if I miss a request?
Nothing bad happens and they stay blocked. Silence is a safe outcome by design. If it is genuinely urgent they have an emergency override that does not need you at all.
Am I responsible if they use the emergency override?
No. It always works, instantly, without asking anybody, because a phone somebody cannot get into is a safety problem. You are told afterwards. That is the whole of your involvement.
Can I hand the key back?
Yes, at any time, and you should if it stops being something you can do well. Their blocking carries on for a couple of days so they have time to ask somebody else.