Sammy Arson, flirting with the hard left :3train guard asked for tickets, I showed my ITSO card expecting needing to wait for them to scan it and validate that I'd tapped in, they just go "yeah that's fine"
twice now that's happened (only ever needed to scan to prove once ever) 
one day I'll be brave enough to play the "show any vaguely rectangular thing to a guard and see if they assume it's a ticket" game
kuriko@theresnotime i’ve had conductors visually check a strip of receipt paper with an (aztec) code, which was a bit wild but can’t be depended on since most conductors i’ve seen would still scan it
@theresnotime update: within 30 seconds of this previous reply a conductor checked my oyster card with a scanner