Anyone remember the Metrocard bending trick that worked in the '90s til sometime early-mid 2000s?

You'd just have to find an empty value Metrocard (that wasn't previously bent for this trick), make a partial vertical bend in the magstripe track in a certain area, then swipe a few times and the turnstile would let you in on the swipe following display of the "Swipe again at this turnstile" message.

I think it had something to do with causing difficulty writing to the magstripe track, and the system generously allowing entry if it couldn't determine the last write state of the card, before the whole card got revoked? Or something along those lines.