Does anyone ever need to enter it as a password? Or do you want to use it as a one-time thing? Because seriously, no one wants to enter a GUID in a passwordfield. People have trouble enough as it is, entering WEP/WPA2 wifi network keys. And most of the time, those are one-timers.
@Miyagi: that's the most obvious con ofcourse. They'll have to write it down.
