[jaxtellerSoA]

>which implies already having high privileges. (How do users with such high UIDs come into existence?)

I am not so sure about that. I work at a smallish, place and by default my AD account has UID of 945004649. Still under the INT_MAX but not that far off. Our domain controller is running Windows 2012 R2, and nothing was changed or touched regarding UID's, everything was left at the default. We just create users and get whatever UID AD assigns.