I have a pally alt that I run all the time for 5 mans and sometimes I raid with him as well. I've never refused to buff anyone in a 5 man honestly it's the cost of a reagent that does not cost alot to begin with. I have however run into pallies and priests that do refuse to buff in 5 mans even when asked nice it's nothing but no I'm not buffing just go.
For pallies with PP it's honestly not hard to buff unless you have to change pp around even then it only takes a few seconds. I just don't get some people though.