My suggestion is if you do it, charge for the convenience, I got up to $11,000.00 in accounts recievable one time in Ca. and when I saw that, I decided to start charging, and had an extra form, along with the contract, for the client to sign discussing if the deals fails to complete, payment is due within 10 days. I'm glad it is not the way of doing business here in NY, so I don't do it anymore.