In response to madduck's entry about sysrqd, I just wanted to add something:

Having clear authenticatiin password is, as he understood, in a way, a designing concept. Using sysrqd over the Internet is probably crazy, but using it in a private LAN or over a VPN, is not. We have to reach a compromise.

For example, I won't use PAM, because I already saw PAM unable to response to authentification request on half-crashed system. Moreover, I already refused some patches that proposed to log sysrqd events, because I also already saw system call to syslog crashing and blocking a process.

It's also possible to use a one shot password, and to change it when you have used it once.

Use it, don't use it, I don't care, but it can save your life if it is well used. ;)