How do you rule on this?

NND Sports Fan

VaPreps Varsity
Aug 1, 2002
921
182
43
Team A kicks to B. B returner muffs the kickoff at the B 5 yd line. Ball gets past him and as he reaches for it he kicks it and the ball goes through the back of the end zone.
 

White hat

VaPreps Honorable Mention
Aug 17, 2001
1,322
87
48
That's an illegal kick, obviously.

The result of the play is a touchback. ALL kicks into R's (B's) endzone are touchbacks and because the returner did not possess the ball, the play remained as a kick. So even though the returner helped out the ball with the illegal kick, the result is still a touchback. (It seems like this should be a safety, but it's not.)

Now, how to assess the penalty.... Since this is a kickoff, the only option is to enforce 10 yards (yes, it's now 10 yards, no longer 15) from the previous spot and rekick.