all mine have quick disconnect snaps on the back for that reason.
I used to slipknot them so anyone trying to grab one would go off balance whilst trying. Bit of a trap -- they think they're gonna grab that and pull and pull your neck with it, and instead there turns out to be a couple feet more slack in the lanyard because of the double slipknot construction, meanwhile you are expecting them to go for it and that means you're ready to counter when it doesn't work and they're off balance. If it's not a serious fight you can just drop them with their own momentum. If it's a serious fight their legs will be forward, which is where they keep their femoral artery. :)
I'm getting more polite in my old age, and now I just fit them with quick snap disconnects -- a quick jerk won't disengage them but a hard one will.