Imagine watching dozens of strangers partying in your home and some stealing your things — and there's nothing you can do to stop them. That's what Charlie Brem says happened to him when he listed his Arizona home on Airbnb. He thought he was renting to a family of seven people while he was on a trip to Boston. But when he was away, a neighbor told him there was a loud party going on in the house. Brem checked his security cameras and saw the rambunctious gathering for himself.