Yes.
The thought of any Tom, Dick or Harry being able to act as Judge, Jury and Executioner is quite frightening.
While I'm against further firearm legislation, it does make sense that Doctors should be able to inform the authorities if a certificate holder is suffering from any kind of mental disorder.
Lets not forget, these incidents are few and far between.
I agree with what you are getting at Matt, BUT, if there was some lunatic walking down the street and quite plainly blowing innocent people away, i would do my upmost to take him out. If that meant me grabbing a shotgu