Several reports on Reddit about people getting banned this week as well. Most seem to think it has to do with them buying mass black lotus for thier guild. In many cases my bet is that the person doing the farming was botting, then when the other other person bought something for over 1000g, it looks as if they're in on it.

I'll bet a lot of the current wave of bans is catching people like that - catching not just the botters, but people interacting with them as well. I've heard some of the SM and ZF farms are being botted now.