I built a troll (giant type) for a friend whose sidearm was an MGL-6. Ahhhh, those were the days ...
That said, while violence - gang and otherwise - is relatively common, you also need to look at the level of security in an area, i.e. its security rating. While some crazies (the Halloweeners) will try to rampage through
downtown Downtown Seattle, throwing molotovs at the Aztechnology Pyramid and causing a ruckus, they run a real and
high risk of getting blown away - which is why I think they
probably rampage through the B- and C-rated areas of the Downtown District.
If you want to give your players something of a taste, do this for every mile or two travelled in a vehicle - or even every few
blocks if they're on foot. Make a, let's call it a 'Tension Level' roll - I'd suggest a baseline of 10, but pick what you want - and during any event/adventure in which it says there's widespread rioting and the like, increase the number of dice. In a Z-Zone,
only if you critically glitch that test do you
not have violence occur Very Nearby (i.e. you're within at least Long range, maybe less, of
their weapons - usually pistols, but sometimes machine pistols, smgs, shotguns, etc.) during that part of the journey.
Use the area's Security Rating as the number of hits required for the person/group to encounter violence: 1 hit for E-rated areas, 2 for D-rated, 3 for C, 4 for B, 5 for A+. What will differentiate the various levels of A+ rated zones is the immediacy of the response. In an A-rated zone, a sec-team might not be involved, but at least one is sure to be on its way. (Use the security response timetable for that.) In a AAA-rated zone, meanwhile, as soon as a stray round hits a security team's building, they're going to 'selectively engage' in order to reduce the threat. Whether that's going to kill the combatants or simply drive them off, the security doesn't care - they aren't
here endangering 'our corporate property'. Which can of course lead to the two groups initially involved getting in a running battle as 'border guards' keep them moving along by shooting at them ...
I am reminded of a book that is somewhat Shadowrun-like, but which
especially displays the sort of near-hellhole in which people in D- and E-rated zones live - the violence that happens just as a matter of course. Check out David Drake's 'The Sharp End' ...