I Get Asked About the Dollar Bill

I was minding my own business today, coming through main campus gate after having picked up my brunch, when the most random thing (so far) happened.  One of the security guards called me over to the booth.  I was shown a $1 bill, one of many that were sitting in front of the two busy officers.  He kindly asked me (as kind as naturally-brusque Mandarin can sound) who it was on the banknote.  I explained that it was George Washington, and not Abraham Lincoln--who one of them had obviously thought it was.  I then pointed to their collection of fives and told them that was old honest Abe.

Having cleared that up I left.  For some reason it never occurred to me to ask them why they had the money in the first place.  Probably best left a mystery.