Re: You know what?
@TRT
"It is for the myriad of bootable CDs/DVDs I've got to test hardware, defrag drives, kill rootkits etc."
Presumably everyone can grab the signed versions of GRUB2 supplied by the Linux Foundation or Canonical, and no doubt other major suppliers will provide their own as well.
You might be stuck if you want to use some other boot loader of course.
If you can boot from the rescue or diagnostic CD of choice you probably have physical access to the system and can disable the check (on non-ARM systems).
But for anyone who wants to run dual boot Windows and non-Windows systems, turning the check off permanently is probably not a good idea.
I would feel sorry for anyone trying to develop for ARM, except they have shown themselves to be pretty good at, for example, jail breaking phones.