So the reasons we've been thus far fairly lucky are:
1) The lion's share of this board seems to be older drivers, i.e., not many of us are in our late-teens and early twenties. So the gray hair, premature or not, and the middle-aged paunch, mature or not, might help in that scenario.
2) The Porsche gives off an attitude of exclusivity and legal aptitude. When faced with pulling over a Porsche, a cop is only as good as his day in court, in which case he fears he may lose.
3) It's easier to rouse a moussed-up punk than a bald-headed nonagenarian.