Genius... Pure genius.

Why have I not thought of this

My dad does stuff like this since he refuses to hit us. Stuff like change the vanilla pudding with mayo or put oil in my shampoo.

As long as you take it away at 100%

This can also have the effect of bringing out a latent MacGyver as they try to string together older cables and adapters.

Then they borrow their friend's charger

Thanks for the advice, will do.

They can get a charger anywhere. Why not take it from them run the battery down and when your done punishing give them a dead phone.