Explanation: I had brought a canvas sack -- a San Diego SMOFCon tote bag, as a matter of fact -- in which to pack my lunch, which entitled me to a 5-cent discount. The new-hire checker behind the counter hit the wrong button and gave me the 5 percent discount instead, which shows up as "Senior Discount" on the receipt.
In this particular case, the difference was less than twenty cents between the two discounts, so they didn't bother trying to undo it.
He's definitely new, and I think I rattled him a bit. I paid exact change -- $5.10 -- and he tried to give me five cents change back. I point out that he'd already given me an exceesive discount, so there was no need to overchange me as well.