1) I don't think it's cool when a very active provider will NEVER reply to a reference check especially when it's several clients that seem to use her as one.
2) when i never hear back from a client after I verified them (hmm i think they got in trouble with their provider girlfriend or maybe a discount was offered)
3) when a provider messages a client after they post a review on another provider (like ooo i see you cheating lol)
4) when a regular says he's retiring the hobby to find a real girlfriend and you get 3 reference checks two weeks later (LOL that didn't last long)
Its all fun and games