Kat I have done exactly as you suggest several times. One of two things happens:
1) He ignore my messages and stays out all night and I haven't got a clue where he is or who is with which worries the hell out of me.
2) He comes home, the door is locked, the keys are left in the door so he can't put his in (no bolts) and so he rings D14 on her phone to get her to let him in.
After the convo I had with him yesterday morning he is a VERY troubled young man and whilst I agree whole heartedly that he has to learn some respect I am also very worried that if I push him too far he will do something stupid and I couldn't live with myself if that happened.
One thing I realised today is ths S17 has never had to face the cnosequences of his own actins as either XH or I have always been there to bail him out. So from today I am trying tough love. He didn't get up for ocllege today. I reminded him twice what the time was. He ignored me. So after the second time I calmly told him that I was going to work and that in future I expected him to set his alarm, get up and get himself to college. If he doens't do this I will not be reminding him again. If he gets asked to leave college it will be of his own making and then maybe he will start to realise that I've only been trying to help him all along.
Me 43 XH 45 M 2.7.88 Divorce 7.10.09 Kids D20,S17 & D15