What would you do if you noticed that in a tournament, someone was using homemade cards. (Real cards, but printed at home as opposed to the actual card). Suppose they aren't even playing you... but rather playing someone else and you just happen to notice. Suppose nobody asked you... and you just notice. Would you interject into their game?
For real - I know it is easy to claim in the abstract that you would tell someone "Hey man, you can't use that!", but it can be difficult, at least for me, to interject into someone else's game, uninvited.

