Hexedit: That's obviously cheating, and IMO is the only one on the list that should result in a ban. But a ban is probably unnecessary because the offending player will very likely disappear in a puff of humiliation.
MoD+BE: Abusive exploit. Probably good to mention that it's banned prior to any game that does not allow exploits.
BE+retreat: IMO this is an exploit, but obviously there are a bunch of people that don't agree with me. Probably good to mention rules for this one too at the game start, if you don't want to allow it in the game.
Demon twiceborn, stealing Bogus scripts, broken movement orders, etc: Same deal.
Communions, slaves casting: Did not know this was a bug! I always assumed reverse communions were intentional. KO says it's OK though
.
Filling a lab with slave collars: Get a life!
VoD: I consider the doubling-up of slain undead buggy. And it makes me start thinking about game mechanics instead of the game itself, so ruins my suspension of disbelief. I'll cast it, but if I succeed against a target, I won't cast it again on the same target if he doesn't die the 1st time.
Sickle: kind of unbalanced, but not illogical that it works the way it does. Make it cursed (cannot drop) and horror mark the bearer, please.