A chess related thread get started but become off topice get tranfer to the off topic thread (by the mod.) -no problem.
A topic that get out of hand by flame war/spamming/personal attack is get lock by the mod.- no problem.
So iwhen a off topic get into off topic does go into the trash-can ? :-)
Were the non-chess threads initiated in the non-chess forums? If so, no problem. People who don't want to read about anything except chess won't encounter them. If the threads were originally about chess and the topic wandered away, I guess there could be a policy requiring a topic to split out to a separate thread in a non-chess forum, although personally I don't mind when a thread jumps around. It only takes me a couple seconds to skip posts I'm not interested in-- a lot of times all I have to do is see the name of the poster and I know to skip straight down to the next post in the thread. And if the topic was in a chess forum but was never about chess in the first place, the moderators might move it to a different forum.