Good thing it's not typically a consumer version! If you watch one reboot (or other applications like store POS systems) you can see that it is Windows XP embedded, or nowadays sometimes Windows 7 embedded, which is decidedly NOT a "consumer" oriented OS
It really depends on the vendor. Big names are at least careful enough to do that. The bottom of the barrel white-label vendors often don't care. I wouldn't be the least bit surprised if some of those Windows installations are using pirated keys.
It's perpetually concerning how bad the state of systems like this is. A grocery store near me recently deployed a brand new set of self check-out counters...running Windows XP.
Amusingly the credit card/debit card reader is running Linux and shows the old-school penguin image on boot.
I enjoyed seeing Tux on the boot screen of a seat-back in-flight entertainment system recently. And was also amused to see startup sequences for things like MySQL and postfix scroll by.
I remember when ATMs ran basically plain text terminal software and you had to drive to a bank to get one. It was a real blessing when ATMs started to show up in shopping malls.