Rabid Wombat wrote:

A "duress" PIN which cancels the account would be a good addition; similar to the "duress" code on home security systems that appear to disarm the alarm but send a silent alarm to the monitoring station.

-r.w.

Sure. Could also have marked bills coated with staining UV flourescent powder preloaded for just such an occasion. Optionally, depending on the location of the ATM, emergency lockdown features preventing the guy from bugging out. Easy enough to do....