Is this still true? This is a basic security "feature" that I thought was being removed from most of the Linuxes and that default boot security was being put in place to prevent access to single-user mode.
Hmm, I'm not sure. I think for awhile it was a matter of security through obscurity. I don't recall exactly, but I think it was RH8 or 9 or so, where it was damned near impossible for me to find single user mode flags/instructions from the actual LILO/Grub interface. So they didn't give up the keys to the house, but they still allowed anyone who knew how to enter --single or whatever it was to waltz right in.