We had that exact situation, where one of the players didn't realise there was a wall and kept trying to take the pawn (we'll call it west) and another kept immediately moving it back (so, east). Eventually the east mover moved it and then grabbed the marker to tell a player to do something and slammed it down in front of the north player. It was pretty much the most obvious 'move the damn piece north to go around the wall' move that could have been made.

And none of the rest of us could tell west why their move was bad until after the game, which made it evevn more amusing