One friend of mine says "the guys shooting you can use it to pinpoint
you", but that assumes you are in a "gunfight". I suspect if I carried a
weapon and pulled it, whatever happened would be over quite quickly.
That being said. There is also the intimidation factor...
The rack of a shotgun is probably the most recognizable sound out there
as far as deterrent is concerned .. If a bad guy, or a good guy for that
matter hears that sound he knows he has met resistance, and possibly
someone has just gotten the jump, and it's time to get the hell out of
there if you can or lay down and hope the guy doesn't hit the bang
switch (from a previous post. Similarly, if that guy sees a red dot
on his shirt, or even the trace of the laser after the first volley,
unless he is also familiar with laser clad guns, I assume it would have
a similar intimation effect... It only takes a second of distraction or
second guessing to get the jump on "the bad guy", so I might want that
laser anyway....