The more people she contacted and realized the deposit was more then norm than the exception the more likely she is to be able to find the extra money. Have worked out a payment plan for the deposit with a family in the past as well that I thought would be a great family to work with but never not charged it. I would probably have the interview but be firm on what is owed and why and if you get a bad feeling at that point - make it near the beginning of the interview so you only waste a half hour not more then cut the interview short if necessary saying sorry but the policy is the same for everyone and if she has an issue with it then this is not the home for her and show them the door. That saves face and you might be surprised to find they have found a way to make it work or come back to you in a few days after the interview saying they found the money.