I'm so sorry you have to go through this... and also I'm sorry for the child because a 'goodbye' that takes long is tough for all involved. I have had several parents that decided not to say goodbye at all, well ..... that doesn't help!! So I now give all parents instructions in my (written) policy, a short goodbye and they hand the kid to me and our 'little ritual' is that I wave the parent goodbye with the kid at the window. It works (accept for 1 dad that keeps lingering, he has a hard time with his child crying, the kid is the only one with separation anxiety... it has a lot to do with the way the parents have a cheerful and trusting attitude in the themselves)