The coin check. Any club member may slam their coin on the bar. Everyone present must produce theirs. Last one out — or anyone without a coin — buys the round.
Carry rules. The coin travels in a pocket, not a bag. A bag is a checked coin, and checked things get lost.
The pass. Handing your coin to a stranger who saved your layover is the highest honor the club gives. Then you've earned the story AND the excuse to order a new one.
Golden ticket clause. A golden lottery pull, witnessed, beats a coin check. The house pays.