Witting and Unwitting Private Communications Between 42 PartnersForty-two (42) is a partnership trick-taking game with bidding and trumps. As such, traditional players bid their hands and expect help from their partners to make their bids or set their opponents. How this is done is often subject to how partners communicate with each other without "talking across the table."
Traditional players normally bid their hands and hope their partners can help them make their bid by being able to take the lead when they need help. Other partnerships resort to pre-game agreements that signal what dominos they're holding in their hands. The latter can be described in two categories:
Unwitting communications between partners is difficult to regulate in tournaments when multi-playing cultures come together to compete. Some unwitting players and their partners (and their groups) have their own indicating styles, and they see nothing wrong with playing that way without specific playing rules to the contrary.
So, how do you address "cultural" playing practices when no collusion in the local playing groups applies. One way is to define and regulate specific indicating methods as legal or illegal. This would require known indications to be listed and labelled acceptable or unacceptable. In time, most players will conform to the new standards. The bottom line, however, is private signals of any kind, witting or unwitting, between partners are not acceptable unless their meanings are deducible by experienced players when first observed (or shared with the opposing team).
There will always be those who believe the rules don't apply to them, and they will have to be dealt with on an exception basis (challenges decided by tournament directors). Most players, however, are honest with integrity and will adopt enhanced fairness in indicating if such is adequately defined.
And then, of course, there is the option of doing nothing and continuing the status quo if that is the will of the majority. Private indicating agreements between partners will continue, and those who don't recognize or use privately agreed/understood methods will be disadvantaged in formal competition.
*8 Mar 2021: The Sep 2019 N42PA Tournaments Rules (Rule #17), define "talking across the table" to include private indicating agreements between partners away from the table.