Yeah, all leagues should have a rule for this.
Last night, my team played against Seendio. Despite the match obviously being between an IM team stuck in Open due to ESEA's dumb moveup rules and possibly the worst team in Open, they were very nice about the whole thing. Wish every team was like them. Most are.
However, you'll get teams of varying skill levels that will deliberately try to put the other team at a disadvantage. I wish we could trust people to be nice, but we really can't all the time. :(