I delt with many of these issues while on the board for the San Diego Aces. We had to clearly define the rules and state them on the club website. They are simple such as everyone on your card is an automatic tag challenge (no need to declare challenge). Tournament rounds with others in different groups as optional and declared before the event. I think the Aces rules are too complicated, but here they are for reference. http://sandiegoaces.com/bag-tag-rules/
I hope this helps.