Guranteed Blocked PAT
There is a glitch on the PAT that will allow you to block the kick each and every time your opponent goes for one after the touchdown.
Have your player line up over the center before the snap. When the holder shouts "Ready," press down and the Y button to jump over the line of scrimmage. If you do this correctly, you will be between the center and the holder. Do not touch anyone yet, as you get an offsides penalty.
When the holder shouts "Set", press the START button, which brings you to the pause screen that shows the score, quarter, etc. Wait for one second and press the START button again. You will still be inbetween the center and the holder, but the game doesn't acknowledge your presence! This makes the kick easy pickings now. When the ball is snapped, wait for the ball to pass through you and into the holders hands. You should easily be able to press Y again to jump onto the holder and snuff the kick.