Wow, so much unnecesarry hair-splitting and digression. In live chess it is okay to use a real board if it merely shows the current game position (no moving pieces around to analyze -- do this in your head). Using a physical board instead of the on-screen board is not getting "outside help".
Moving the pieces around is not outside help either.
Live chess is supposed to replicate OTB chess. Online chess is supposed to be a correspondence experience.
So yes, having a second board to move the pieces around in OTB chess is not kosher. So I'd call that cheating in live as well. I don't see what advantage you'd get merely from looking at a second board with the exact same position, so I wouldn't call that outside assistance. You could make a rule against it, but I don't see how it confers an advantage.
Look I agree there's nothing wrong with doing it, but the rule is very clear:
In Live Chess, no outside assistance OF ANY KIND is permitted
how about using a mouse or a keyboard to move the pieces? Okay or not?
People don't move the pieces with their mind? Way too much cheating going on here.