Originally Posted by KG7IL
Yeah, I solved that problem by only buying lights with an on-off switch.
That'll work every time, so long as any potential BG's agree not to look when your light is 'on'.
Seriously though, the original question is always going to boil down to the application. A light absolutely can work for you or against you. And potentially in extreme fashion in either direction. Some of this will be dictated by circumstances, but many of the tripping points can in fact be mitigated by keeping your wits in a difficult situation (often easier said than done).
I have maybe 20 guns, half of them pistols. I own two Tac-lights and only one is mounted. And I'm honestly only about 60/40 in favor if it's actual benefit. But that's my situation. And the next dude's perspective and circumstances can vary greatly.
There is no downside to nightsights IMO.