Well good for you. I would have thought that a clause in the contract signed by both would be enough given that if it was broken then the provider would be liable. I guess I just don't see the large deposit as necessary when a legally binding contract exists. Also, I'm not sure why families would pay it, unless they had first hand experience in this occurring then in my experience people would take the chance rather than shell out so much money. The money doesn't guarantee anything. The signed contract including this clause is what seals the deal and a monetary fee of any amount wouldn't be any further assurance. You say you aren't charging more for a temporary family, but you are, you are just structuring it differently. Whatever works I guess.