I'll be the Buzzkillington here and just say this;
Video games have an effect on people, positive or negative, just like any other medium. For some people, that effect is more severe for themselves than it is for others. To say that "Video Games don't cause any violence!" is just as ill-informed and agenda driven as those who say "Video Games are murder simulators!" and it's detrimental to the science of understanding how the brain works. Some people are just crazy and anything could set off the fuse, whether it's a video game, a movie, or a book.
That said, that old granny had that Uncharted disk coming. Uncharted told me she still liked to play Nintendogs, and that game made a crack about Metal Gear Sold that I just couldn't stand for. I think it all stems from that one time GTA4 snuck me in his "candy van"...