Well - can we have one?

Sure. What keys do you have bound to primary, secondary, and tertiary? If you're using the defaults, copy this into wgaf.cfg

### These are the defaults, you should already have them in wgaf.cfg
# bind "v" +Shoot3
# bind "c" +Shoot1
# bind LMBUTTON +Shoot2
# bind RMBUTTON +Shoot1
# bind MMBUTTON +Shoot3

### Here's the actual safety aliases:
alias safety_on "bind 'v' ''; bind 'c' ''; bind LMBUTTON ''; bind RMBUTTON ''; bind MMBUTTON ''; alias safety_toggle 'safety_off'"
alias safety_off "bind 'v' +Shoot3; bind 'c' +Shoot1; bind LMBUTTON +Shoot2; bind RMBUTTON +Shoot1; bind MMBUTTON +Shoot3; alias safety_toggle 'safety_on'"
alias safety_toggle "safety_on"

### And here's an example bind for it, this would use shift-S to toggle the safety
bind "S" safety_toggle

i have to ask: how trigger-happy are you that you need a safety?

New players and those who play other things that require a lot of clicking have accidentally fired off weapon, sometimes with bad results.

So, after making that alias I'm curious. Why is primary fire +Shoot2, and secondary +Shoot1? I realize it'd be a pain to change it now that it's this way, but how did it come to be so? And actually, I'd almost say it would be worth it to change, for clarity. Sure, we'd have a while with people gettting freaked out that their firing was switched, but it wouldn't be tough for everyone to change their binds.