I have done this twice with my daughters best friend after her parents threw her out. I had to send her packing both times, she promised no- bullshtuff and both times she found a way cause just that. The first time at 18 so she had a stable place to live while finishing HS, and again at 21-- after her 2nd DWI -- her roommate told her she could not live there anymore. She seemed so much more in control of herself than she The first time she promised to pay me 100 dollars a month, but it came down to me throwing her out.. The second time she promised me no shenanigans.. My AD was deep in the midst of her addiction and I told her I could not have any stupidity.. It started out the first week she was here.. She went on a binge coke and Alcohol(later found that out) came home vomiting for 48 hours went to the hospital.. then came home to my house to call a friend to bring her Xanax so she could calm down --- ended up at her parents out at 5 AM high as a kite... She promised no more..and really seemed remorseful.. But then a week later she was dragging my AD out to get more coke(found this out later too) at least 5 times she did this.. then on my AD's Best friends Birthday they went out to celebrate.. and my AD got really drunk and the Best friend shoved a baggie with a straw in it and told her to inhale.. because my AD was having more fun that her (it was "her" birthday) and told her it would sober her up.. When this all came out the Best Friend was sent packing once more. I get that my AD could have said no.. but she did not... now my AD is in rehab by choice and the Best Friend is in Court Ordered rehab...