Asking a question is fine, posting replies to questions is fine, asking for details in a pm is fine, telling someone UGPM is not. Why? It's useless and unecessary. If the guy get's a pm the forum informs him of it.

Look at it this way, if you were selling something and your thread was permanently stuck in the 10th page because people spam ugpm or some other unecessary post like Happy new year, happy wednesday or w/e everytime he wants to, would you be happy? No.

Also, if you see something you think is in violation of the rules, report it. I find it strange that people keep saying they see such and such is breaking the rules but fail to report it.

I'm not sure, I don't handle trade zone stuff, but I'd guess so. If you think someone is doing that, report it and we'll look into it.