It would be a "unique" situation. Most AMTs (not all, but most) only dispense $20 bills, the rarer ones will dispense $5s or $10s, and they're rare enough that I make a note of them. I have never encountered an ATM that gives a $50.

Your best bet of happening into a $50 is if you go to a bank for an in-person withdraw and they ask you for preferred denominations. Generally the money is dispensed in $20s even there unless specified.

Your second best bet would be if you're selling something "on the side" and the purchaser uses a $50 in a transaction, which I would say is also rare these days, most people use Venmo or equiv.

Your best bet of handling a $50 is probably as a bartender, or of course as a bank teller.

I have held $50s a few times in my life, and even my reaction is "huh, a $50, don't see those often"