If we offer to accept $ 250 and you think that is a lot of money, then we believe it will make you be extra careful. If that is acceptable, we will agree otherwise, as you said, we can not help you. We would like to have you but we believe human nature makes all of us be more careful. (including us, as we have had to pay a deposit when traveling. abroad,,,,,,,and we both were very cautious,,,,,,,_).
We do not want your money, we just want you to think twice about how you treat our condo. I am feeling there would be not problem, but it is our policy for all. So, if we can agree on the $250, then we can all be o.k.