When I worked as a bank teller briefly, we had this planned out. There was a stack of bills (usually 10s, but it was kind of random) that we were only to give o

When I worked as a bank teller briefly, we had this planned out. There was a stack of bills (usually 10s, but it was kind of random) that we were only to give out if we were actively being robbed. They were indistinguishable from regular currency to avoid suspicion, but the serial numbers were recorded for tracking purposes. This was in a small town bank, and I'm sure that larger banks have more sophisticated policies. I'm curious to know if ATMs have any similar features.