[Waterluvian]

Like a fake ATM PIN number that shows only $28 in your account and signals authorities.

[throwawayish]

Actually does not sound like a bad idea.

[_nedR]

The idea isn't new but it never really took off.

http://www.snopes.com/business/bank/pinalert.asp

https://en.wikipedia.org/wiki/ATM_SafetyPIN_software