The Mercy Rule (Or Run Rule If You Prefer)...

...I agree GBuddy. I don't think asking a player to not give 100% is a good idea.
I also agree with Cheeze on his takes of this issue.
At anytime, a coach can "call the dogs off" in a respectable manner, one that will not demoralize the opponent.
Umpires can help out too.

If you're in sports long enough, eventually you'll be on the demoralized side of the equation.

Sidenote: Lou Holtz said that when his team was way ahead, and he put in his 3rd team guys, and they continued to lay the lumber, he only asked them to play hard. When the opposing coach questioned his philosophy, 'ol Lou said, "its your job to stop my team from scoring, not mine".
Fishman

 

Actually a similar situation just happened. McDowell High basketball girls played a team they knew couldn't keep up so the starters played less than 2 minutes the entire game and the moved 5 JV players up to Varsity just for this one game so the other team wouldn't get beat that bad. The score ended up 51 to 14. It was 11 to 0 when the starters came out after playing only 1:42.

 

I'm not sure what I would do if the opponent walked 15 in a row, swinging at everything would probably cross my mind. I just would try not to make it an every game occurrence - though it seems that my team really likes those high (and out of the strike zone) pitches anyway...

 

At the Middle school I coach at When the score gets out if hand I have the girls go base to base no stealing or advancing on passed balls / wild pitches. If that don't work I have a talk with an umpire (quietly) and tell him to watch my girls as they tend to leave early, and yes my girls know when it is going to happen, It works. Sometimes I just ask the other coach if they want to change up.
It gets us out of the inning and does not hurt any feelings on either side.

 

There are ways to gracefully get out of innings and games without hurting the othere team, most of them have been discussed and mentioned here already, just let me add, make it look as though you are still competing, it hurts the pride almost as much if the opposing team see that you are trying to end the game. (almost but not quite as much)
Just make it look as though the other team really made the plays...

 

We played in a World Series tournament a couple of yrs ago and we were beating a team 18-0. We had the bases loaded and no outs, so our coach had all 3 base runners lead off before the pitch was thrown (triple play). As the other team got to there dugout, they made taunts towards our team, giving the choke signal and holding the fingers in giving the Loser signal. I blame the opposing team coaches, because they did nothing to stop this unsportsman like conduct. This was our coach's way of not running up the score.

 

In a HS game last year, the start was delayed by rain and storms. This field has no lights and our original start time was 5pm. We finally got started at 6pm and by the 3rd inning, we had worked an 11-0 lead. With the sun rapidly approaching the horizon, we explained to the girls that we need this game to be over at the end of the 5th inning and it needs to happen before dark. The girls went up opposited handed to bat. Small problem......they were getting hits batting opposite. So, we played small ball. Nothing deceptive, we showed the bunt early and laid the ball in play. The defense kept making errors. It seemed that the other team was making errors on purpose. So, with bases loaded and no outs, we had the runners step off of the bag early. Not all at once, but on three consectutive pitches with the batter getting the take sign. Next inning went a lot quicker and we finished before dark set-in.

Sometimes, ya hafta do what ya hafta do.

 

Sounds to me like that should only have been 1 out. It's a dead ball if the runner leaves early. But what if they did leave early at precisely the same moment? Would that be 3 outs? With only two umps they wouldn't be able to tell--and one of them was suppose to be watching the pitch.