I think you are doing all that you can, have you tried stating at the phone interview that your closing time is not flexible and only accept families that have a pick up time prior to x o'clock? I guess some people feel that maybe once you meet them then you are going to change your rules for them be use they are that awesome...or maybe they think we are all desperate for clients that we will take any family. I feel your frustration but the right family is just around the corner.