I would say one could be thanked for anticipated cooperation. I have seen similar statements in business letters, for example, "Thank you in advance for your cooperation."
The writer is trying to put the reader in a position of being more likely to cooperate, particularly in a situation in which that cooperation might be questionable. Even in cases in which the cooperation might be assumed, there is nothing wrong with thanking someone in advance.
This reminds me of what I used to do with my children, when they were younger and wanted them to do some chore I knew they did not want to do. I would say things like, "Thank you for emptying the dishwasher." Then, of course, one of them would say, "But Mom, I didn't empty the dishwasher." Then I would explain that I was thanking them in advance. It got to be our little joke, but the dishwasher did get emptied!