If a team is up 6 and the other team is driving do you feel the game should be impacted by a penalty? Do you think with .05 on the clock and at your own 30 yard line that you possibly be given a first down on the 1 yard line? Shouldn't the team that's ahead be given the benefit of the doubt?
I feel that if a team is up 6 and the other team is driving and the defense interferes with the receiver there should be PI at the point of the foul. If you don't do this then you encourage the defender to foul. I feel the defender should never be given better field position by committing a foul. It takes away from the skill of the receiver to make the catch which is an integral part of the game. The receiver should always be given a chance to catch the ball unless the defender can make a play without interfering with his ability to catch it.
The same thing could be said of a runner who makes a 30 yard run. If a defender made a personal foul on the runner and was penalized 15 yards from the line of scrimmage you would have personal fouls on any run over 15 yards. It would encourage the defender to foul.