Mods? Serebii bans everyone for no apparent reason, so if he was banned it was probably for being rude or something. They do not punish you for trading hacks. According to what I can see, he is banned for just a week, he has pretty good overall reputation and friends.
And about the site, no, we usually gather event info and we are composed mainly of Japanese members who attend the events there. We only check DS events ><