[kovacs_x]

I've always wanted this for payment cards- alternate PIN number that instantly blocks cards and notifies banks security (ie. in case when someone extorts your PIN or wants you to use ATM forcibly) and returns something like "Not enough funds" or similar.

[qrobit]

I saw video "do that if you are forced to enter your card PIN" where they tell you to enter your PIN backwards, which will allegedly be accepted as a usual PIN, but additionally notify authorities.

Unfortunately none of the banks I was client of did that

[extraduder_ire]

I think that's an urban legend. it appears to work sometimes as some ATMs don't do anything with the provided pin until you get further in the transaction. A surprising number of ATMs also do "offline" verification, where the card itself is the only thing validating the pin and the transaction is send back to the card processor later.