not sure how that was considered a late hit - he had his tip toe on the out of bounds line when he got plastered. There was no way he could have stopped and it was a split second after he barely stepped out - probably couldn't even tell he was out.
They probably threw the flag because the hit was so nasty. It was funny - you could hear one of the USCjr staff/coaches cussing saying something along the lines of "throw that ****** out of the game" and "this game has no place for that ****" when the hit looked pretty clean.