only if police and judges are stupid.

So depends on their mood, corruption, and whether they want to get you.

If you live in a shithole country that's always the case.

I’m sure the police would come to my door, but I could show records of it not really being “my phone number”.

Family plans are pretty common here, so I wouldn’t expect too much friction.

I would absolutely cooperate (obviously through a lawyer) with records if someone else on my family plan did something illegal.

I also have records showing that they pay me for the line.

Also yes, it would be a huge hassle. The probability of that happening is small, and I’m willing to risk it like many other things in life. I only do this for very trusted people.