I've used www.Guestchecker.com for about a year now. It's a renter blacklist posted by other short term accomodation providers. You can report the guest for trashing your property, being rude, noisy, etc. You can also look up your next guest to see if they've been reported by someone else. It's especially useful in a small community like an island. Bad renters usually stick to a certain area and the sooner you let the others in the area know about them, the better.
I hope you held a deposit on them.
Hello from the offices of GuestChecker!
My name is Shane. I am one of the founding members of GuestChecker. There has been a lot of talk about our service on the HomeAway Forums. I would like to open the field and answer comments, questions, concerns about our service on our new forum here: http://community.homeaway.com/message/10427#10427
I look forward to helping a community that has help us so much over the last 12 months.
Talk with you soon!