OK confession time. Back when in 73 when I worked at DD as a teenager, I was mopping the floor and doing the dirty work. The cashiers would have a tip cup, that kept filling up which didn't match the customer activity.
I spotted it questioned the cashiers and the old ladies told me to mind my business. I then threatened to tell the boss (who makes the donuts) if they didn't explain. What they told me is that donuts were $1.50/dz, they would ring up $1.00 and place 50 cents in the tip jar. Essentially stealing. Being a teen, I kept my mouth shut.
Well a couple of months later, the baker/owner put me on the register. I was around 16 years old. . . . . . . . .
$0.50 in 1973 is worth $2.93 today