but incidentally the FOSE byproduct has been ever so welcome for me
... ->
Before things get totally out of control due to overzealous mods:
FOSE does not (!!!) change any protection method of Fallout 3! Neither FOSE nor OBSE alter copy protection schemes in any way!
Fallout 3 simply doesn't have a disc check in the main executable, but in the launcher. For Oblivion it's the other way around (disc check in the main executable, but not in the launcher).
Sorry to be a pain about this, but I've seen what discussions can do here if the wrong people get this wrong. FOSE does not, in any way at all, change Fallout 3's protection scheme.
Don't believe me? Put your Oblivion disc into your drive and doubleclick on Fallout3.exe in your Fallout 3 install folder. FOSE does nothing in this regard (as seen if you start Fallout 3 directly) - Fallout 3 doesn't come with a disc check in the first place, therefore FOSE doesn't alter anything in this regard.
It must not, see. And if the wrong people think it would do so (which it doesn't!), it can end very badly. So let's not go there, and let everyone know:
FOSE does not remove any disc check.