At least for Parallels, if you read the instructions, it says the first time you start up Windows Boot Camp in the VM, do not activate until it has fully instal

At least for Parallels, if you read the instructions, it says the first time you start up Windows Boot Camp in the VM, do not activate until it has fully installed Parallel Tools and it's drivers. Something in those drivers, which I presume is legal, prevents the infinite activation loop.