I try to insist meeting up with the model before a shoot.
I always insist on talking/emailing the model directly, going thru a 3rd party is a recipe for disaster unless you are dealing with seasoned agency girls and reputable agents.
I lay out clearly with all models what is expected when we meet up, there is no surprises.
There are so many things that can go wrong. Assuming that the model is genuine, not merely playing the role of a princess-biatch, it's my job to make sure she is comfortable, and therefore, no unforeseen problems
Based on TS's thread title, I am assuming that we are talking about the princess-biatches. There is nothing we can do, but to weed them out and try not to work with them. If the model starts showing bad attitude at a shoot, I will politely halt everything and call it a rap.