Pretty curious since a lot of people are all "BWAZAAAH HACKERS RUINED EVERYTHING!!" or at least have been.
I, for one, seem to have missed pretty much every hacker/modder around. Only time I noticed one was when I was gifted that nice $90 million. There could have been one later on too, but I don't really bother to kill people to find out if they have god mode or such.
As for the results of the hacks, then I could say that I have seen a lot. For example level 40's and below having Chrome Adders (or other super cars) and such.
So, what hackers and/or modders have you encountered? And if more than once, then how often?