I'm not sure how it works now, but a few years ago it was illegal to use more than one copy of Windows in this way (provided that you already have a purchased copy). If you wanted to have two instances, you had to purchase a second copy. I'm not sure what the relevant terms are for macOS now apart from the fact that in the old days VMware had an artificial block you need to remove in order to run Mac OS X. It would b…
AFAIK you can use Windows unlicensed as long as you activate it after evaluation. You're right that you can only run one instance of a given Windows product code on a machine for long-time use, though. The last I heard about the macos situation is that virtualisation of macOS is allowed as long as you do it on Apple hardware that you have a license to run macOS on. You can run as many virtual machines on your mac as…
No, the EULA says:
> (iii) to install, use and run up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software, for purposes of: (a) software development; (b) testing during software development; (c) using macOS Server; or (d) personal, non-commercial use.