I'm all for a physical switch.

Most of my customers would not be, however.

Then again, I see writing to the partition table / boot sector as on the same level as flashing firmware; it should only be done when absolutely needed and by someone who knows what they're doing and quite qualified. Which would put me rooting for a physical switch even more (I'd have less customers, though).

But the question still begs: Why are we allowed to write to this stuff from userland? Even with admin / root privs?

Or, you know, disable the ability to write to the boot sector / partition table without specialized permission.

One time toggle in the bios means you can write to partition table on next boot. Want to write to it again? Toggle it in bios again.

Also, why can we write to the partition table and bootsector from userland again?

You can already have Froyo on your capitvate; I'm currently running it now.

Look at the cognition or perception roms from XDA-developers.