_Even_ if you run the MS-DOS kernel in DOSBox, the builtin DOS literally leaks through in many places (e.g. many API services still available instead of crashing), with only some of the more recent forks even trying to hide it.
There's also an adversarial aspect to this. Some emulators try to avoid detection and a lot of software tries to detect if it's running under virt for various reasons, eg. to stop cheating in games or stop reverse-engineering. (virt-what is deliberately not adversarial, it's very easy to "trick" it if you wanted to do that)
Example: There is (was? I don't actively follow the community) a patch set for a particular piece of VM software that made it undetectable to anti-cheat in games.
While I don't use said software (I have a casual interest in it only...would be nice to get more games working on Linux), I have to disclose that I'm against anti-cheat mechanisms. I'm a software engineer, and I've worked on a few smaller games, and know the overall structure of bigger ones, and I don't think I've ever seen a game use good practices in multiplayer. Instead, they usually rely on client side code and lean on anti-cheat software to stop cheaters.
What's WGU in this context?
> which makes enough sense since if you're in a VM they can't see your full screen
Presumably they can't also see the screen of another device...
When taking a test they have a proctor that's watching you on a webcam, and they make you pan the webcam around the room to ensure that there's no obvious way to cheat, and they make you share your screen to ensure you only have a browser running.
It’s perfect for all parties, and doesn’t intrude on your personal living space or devices.
Well that level of intrusiveness would just make me come up with something overly complicated just so I could prove that I could cheat if I wanted.
That's why they make you share your screen; obviously there's plenty of ways to fool that but the goal is to make it so that cheating requires enough effort to where it's probably less effort just to study and do it right.
They just want to make it difficult enough to catch most.