Bad Club

Enter the two-word passphrase you were given when you picked up your badge.

Cards open soon.

Pick up your badge at the door and the organizer will check you in.

Talk to people. When a conversation fits a square, tap it and enter their badge number.

That is a bingo. You are in the raffle at the end of the night.

Their badge number

I'd like to try this too
Lets the organizer include you if this becomes a plan. They are not told. Note to yourself (private)