I think that a "mercy rule" could be more damaging than getting beat by 15 goals. If you get beat by 15 goals, you could find solace in the fact that your team "fought until the end" or maybe you get a break and stick a late goal in to mkae it 15-1. Or maybe your team doesn't allow a goal in the last 10 minutes. As the losing coach, you could then focus on that instead of the 15 goals. If there is a mercy rule, the other team will try and put 10 goals in ASAP so that they can go home. This makes the game a waste of time for both teams! Why do people keep mentioning a "mercy rule" instead of restrictions. For instance, after you get up 5-0 on a team, your team must complete 5 passes before they can go to goal OR all goals must be scored from a cross OR the coach takes out all startes and put in all freshaman, sophomores and less significant players. Just like it is not right to run up the score, it is also not right to ask a player who maybe has never seen the field to go in and not try for the sake of the feelings of the other team. If this is the case, when will teams with no JV get younger players experience?
If there is a "mercy rule" then teams will not brag about how many goals they scored but the fact that they scored 10 goals in 20 minutes and that they beat the other team "into mercy". Then what? Do we say that a game has to go at least 40 minutes but that any goal after 10 does not count? There is no fair way to contain scoring or poor sportsmanship except with coaches that understand how to properly implement restictions. If a player violates one of the restictions, then that player is benched. Teams are going to lose and lose bad in all sports. That is just the nature of competition. Coaches can use games like that as a "practice" by correctly implementing the restrictions system. This gets the winning team needed work and maintains the dignity of the losing team.