As a referee I'd say that a penalty was the right decision. The keeper clearly swung out his leg and caught the striker with his boot, possibly his studs. The challenge was reckless. The fact that the striker was looking for a penalty doesn't make a difference.
Regarding the vuvezelas it was definitely much quiter at the South Africa game than other matches.
Last night, after watching the game on TV, as I tried to go to sleep I could still hear vuvuzelas ringing in my ears and this kept me awake for an hour or so.