Gta:vc - Holy fucking shit.

[Lord Magus]

start over, don't turn off the system, and then what about the ride home? does it have a mystery battery i can plug it into so that i don't lose the stuff i do while i am down here?

There are these places that, like, you can go to, like, EVEN when you're not in your home town, like, because they have them everywhere, and like, BUY a whole brand NEW memory card.
OR...
you turn on the game, eneter a bunch of cheats, and go on a killing spree.
DUH

Kindred..
it won't corrupt your game, but some of the cheats effect how the pedestrians act towards you and CAN'T be turned off once activated. While it's all fun and good to occasionally start a mass riot.. it MIGHT be tough to actually play through the whole game constantly being shot at by random people off the street. THAT'S why it warns you.. in case you put in one of those codes.
(I think there's an "agressive pedestrians" and a "mob riot" code, one is they keep killing anything that moves, the other is they all try to kill just you)