If the defense commits a personal foul on a touchdown, the penalty yardage will be added to the spot of the ensuing kickoff. So the scoring team will kickoff from the 50 instead of the 35.
The issue is that most kickoffs are now easy touchbacks. The average starting field position after a kickoff is the 22. So the penalty is very unlikely to negatively impact the offending team.
What made me think of this is a play in the Redskins / Cowboys game on Thursday. After Pierre Garcon scored a big touchdown. Mike Jenkins, the Cowboy safety caught up with him in the back of the endzone and gave him a shove out of frustration. The Redskins kicked off from the 50, which resulted in the same th