Stephen Sprunk wrote:

Hmmm, Canadian bank machines routinely dish out our $50's, though the
machines are usually identified and at locations where "regular" $20
dispensers are also available.

US ATMs generally only dispense $20 bills; it makes them simpler and
requires less refilling if there's only one bill type. There are still
a few that give out $5 and $10 bills as well, though they're rare. Ones
in casinos will give you $100 bills, since they accept them at the
tables and that's where they want you spending your money. I've never
seen a US ATM dispense $50 bills.

There are at least 3 ATMs within a 5 mile radius of my residence that
dish out $50 bills. So they do exist.