arawnsley: "Using RO4+ ROM images on RPCemu is, I think, pretty much a blatent licence infingement, but hey, this is the RISC OS market - noone can afford to get litigious!!!"
Using a RISC OS 4 (or RISC OS Adjust or whatever) that was properly bought and is not used in another context is of course perfectly legal on any machine - including RPCemu.
Concerning Windows OEM licences: Microsoft's view of things have been tested in court (at least in Germany), and Microsoft lost. As a result, it is perfectly legal to resell OEM licences, and it is perfectly legal to do whatever the user wants after he has bought it (bundled or unbundled), including running it on a VM. I suspect the same rules also apply to RO4 bundled with V-RPC.
Moral: if you sell something, you can't arbitrarily restrict its usage.