No, because we already do more-or-less. I mean over a certain period of time you can run out, but once you allow enough time to pass you can use as many as you like.
I didn't try it with two different installations of one OS on the same machine, but it's necessary to unlock LFS for two (or more) different OSes. It's actually recommended to keep separate LFS installs for each OS to not have to unlock every time you run LFS from the other OS.
Err, I'm not sure if multiple accounts is against the TOS, please link me to where you found this? Also @OP You can email victor if you ever need more unlocks, which I don't see why you would.
Multiple users of one account (account sharing) is illegal! If you want,you can buy for yourself multiple accounts,I don't think devs would mind extra money...