The chess.com rule: "You may NOT get any help from any person or any chess engine that analyzes your specific position, including tablebases."
I kept an eye out for this 'trick' in my first tournament. If I saw two games following the same line past the opening I would probably go on vacation a couple days so our games could diverge. If they still persisted I would alert the chess.com staff.
Suppose you are pitted against two much stronger players, one as white and one as black. Is there anything in the rules preventing you from playing them off against each other? That is, wait till white moves, then make that move against black, and so on ... [This guarantees one point, no more and no less]