[hal]

I suspect that there several mitigating factors that need to be examined here. Have you ever noticed just quiet things are in the still of the night? No sounds of traffic? No sounds of dogs (assuming you live with dog owners that shush their dogs excessive barking). Have you ever noticed too, that you don't hear the sounds of children playing? Then take into account that those people who MIGHT hear, also have to make an IQ roll upon hearing it, to know where the shot came from. Next, they have to even know what a suppressed gun sounds like.

Then you have intervening obstacles that can act as sound baffles - vegetation being a good example of this. Then, there are hard surfaces that can redirect the sound such that it can sound louder. Urban environments can be tricky when it comes to gunshots.

So, as far as realistic tactics for sound suppressors? I'd suggest that you may want to assess a -2 penalty to IQ rolls for those who haven't really HEARD gunfire before (Television is NOT sufficient familiarity for that). I'd also consider that some people are behind walls and doors and such, which will add to the range penalties for hearing sounds. Then you have televisions that are on in the homes, or radio's or even people who listen to their IPDDS with their earbuds. Factor in that some people will be on the phone, and others are just plain focused on what they're doing that they might hear a sound but not feel the need to investigate it.

As for the sound suppressor user? The real question isn't whether or not the shot will be heard, but whether it will be acted upon. Someone who has served in the military or is a gun-owner might hear the shot, and recognize it for what it was, but will they recognize the direction it came from? Even if they did recognize where it came from, will they be looking in the right direction by the time the shooter has done what he will and then moves on?

There's a lot of factors that go into the situation, that the GM has to make decisions about and take it from there.