On my last visit to Vegas I noticed a new type of slot machine. This one had a colored light ring around the card slot. The ring was red if no card was in the slot, green if there was a card and a person was playing the machine. If the card was abandoned the light would change to yellow.

This was great, I thought, for finding "forgotten" cards. But I noticed that after a few minutes the yellow light started to flash, then after another minute or two the card would dissapear inside the machine.

So, if you see an abandoned card:
If the light ring is GREEN, stroll over to it.
If the light ring is YELLOW, walk over to it.
If the light ring is FLASHING, run over to it.