It's always vague about the known folders, and hiding the details is arguably the point of them, so you have to teach users less if you move them around in a managed environment.

This would be fine if two locations with the exact same address didn't exist.

Not sure what you mean by "the exact same address"? At least from what I've seen "Documents" always points to exactly one folder, and explorer shows only a view of that folder?

I've had two separate "Documents" folders on a few different machines before. I never used those folders, but they both showed up in my home directory and could contain different data.

I'm sure they were something different if I dove deeper in cmd, but I never cared enough to figure it out.

Isn't Documents actually a library and the single default folder (and default default save location) in that library since Win 7?

I had libraries hidden, so I had to check: there's both: the Documents folder, and a library that contains just that folder by default. So yeah, that seems unnecessarily confusing.