Colts-Jags block in back.

[Fiji07]

Watching the Colts-Jags game yesterday and there was one play where I wasn't sure how the penalty enforcement would go for NFHS rules.

Play: K 4th and 5 @ approximately K's 30. K1 punts the ball and R1(returner) waiting for ball at around R's 25. K10 is blocked in the back at about the R30 and is blocked into R1 who proceeds to muff the punt and the ball is recovered by K at the R23. Originally flag was thrown for KCI, but after discussion officials ruled K10 blocked in the back into R1 and have flag for block in the back prior to end of the kick. K declined block in the back penalty and took the ball at the R23.

How would this penalty be enforced in NFHS, if K accepted the penalty and if they declined the penalty?