The NZ government is requiring use of proprietary software to do our important tests.
Some of them will detect if using virtualization. For example http://safeexambrowser.org/ by ETH Zurich
Ironically enough, it is free software https://github.com/SafeExamBrowser
You can figure out the checks and make your own patches to Qemu.
I managed to get mine working.
Edit: SEB now checks for browser integrity so this is no longer relevant.