Something Off About That Comment But I Can’t Put My Finger On It

(We’ve recently started up a finger-scanning process to replace our security codes on our registers. It’s still new, and everyone, including customers, are adjusting to it; to give discounts, the manager needs to scan their print. A regular has ordered his usual and gets a discount on his order using his senior card.)

Customer: “Oh, I need a senior discount, as well, please.”

Me: “All good. Just a sec.” *calls out* “[Manager], can I get senior, please?”

(She is finishing off a burger, and things are busy, so she runs over to press her print and runs off again. The customer notices the scanning and leans in close.)

Customer: “You know how you can fix that?”

Me: “How?”

Customer: “Cut her finger off.”

(He pulled away casually and paid for his meal like nothing had happened, leaving me bewildered.)