people run because we are all inherently selfish although we often care for our friends (but some may say that is selfish too). From a selfish standpoint, the reason to run would be if the punishment for stopping is great enough where it is worth taking the risk of running and dying (or killing others and getting prosecuted for that). Examples would be if you're a convicted felon facing the death penalty or if you've got 2 strikes against you and you don't want to be buttraped in prison where the state doesn't give a damn about your safety.
Street racing would go on a criminal record, so getting caught could ruin your life as to future employment. But I'm thinking most people who would think of that would count that as a deterrent to street race and not race.
However, like I've said before getting convicted of something you didn't do like street racing (which could ruin career opportunities), could drive people over the edge to do things they wouldn't even think of doing.
Perhaps if I'm an almost dead 85 yrs old and bitter and don't care about anyone or anything I might do some crazy stuff like street race and run from the pigs. And pull out my rocket launcher if they corner me (I can use it on the helicopter too!). It's fun when you got nothing left to live for hahahaha.
But wait isn't that something to live for?: the fun that you can have when you have nothing left to live for???
I doubt it, but who knows, I might be the street racin' Grandpa.