When playing in a mismatch, what obligation does the team with the lead have to make the game respectable?

The best I have heard is that if you have a large lead you should never put a 20th point on the board. I am specifically talking to the HS Varsity level. In the non-hot beds, there are plenty of mismatches and some coaches just don't see themselves as having a obligation to help grow the game. All thoughts are appreciated.