I think I'm going to stock up on Sacajawea's and start spending those exclusively, to seek out such morons.
You can still get 50 cent pieces and $1 coins (non Anthony/sacagawea) from banks. It's fun to spend those. People get all confused.
Back when I worked at a mcdonalds, I used to keep $2 worth of small change in my pockets. Old coinage would be in the tills all the time, and once you got used to handling money, you could feel what coins were not normal. Set those aside, and do a swap. Management allowed it, and even did it themselves when they had the time.
Ended up with a few silver quarters, a 1903 indian head penny, a steel dime, various WW2 era coins, a few from the 30's. But, the best was when this guy came to drivethrough, and offered to pay with a 1920 peace dollar that was in mint condition. Needless to say, I paid for his big mac meal myself, and pocketed the coin.