Punishing player for indicating moves to other team players I am arbiter myself, but I don't know how to treat player in team matches who try to indicate other players of their team what move to play in position they are in. If they won their game I might first warn them and at the second time lower their score to 1/2 (to 0 in case of a draw), but if they lose their game, there is no way one can punish them. They have literally nothing to lose. According to FIDE rules, they become a spectator one can only exclude from the room. And even in that case, nothing can stop them just to not care and stay anyway. For the refference, we're talking about low contest, like regional once where most of the time the arbiter is actually a player of one team as well.
In a low contest regional type tournament, I'm assuming you don't have to abide by FIDE or USCF rules. Given this, I would suggest the following:


Warn them the first time you see this happening. Say that the next time you see this anytime in the rest of the tournament, their team loses whatever current match they're playing. So not only does one player lose a game, but their whole team forfeits the entire match.
Enforce your ultimatum from step 1 if you see them cheating again.