I'm just saying I highly doubt that. They would have to prove that the other school knew the ins and out of their rules regarding CTE since it is not the same across the board. I don't see the benefit of this, especially when gyngyn said that seats going unfilled is unlikely. It's fun to think about, but probably not a priority to these schools. I'm sure they have bigger fish to try then trying to get in a legal battle with another institution over one student.
I respectfully disagree. They only have to show that they had a CTE, the other school had a way to see it (the CYMS report they could run), and the other school interfered with it. Ignorance of the law is never a defense. Again, it would never be over one student. It would be to stop all of the higher ranked schools from poaching lots of their students, year after year, after they have made commitments, in order to bring some order and predictability to the construction of the class.
I think what you aren't getting is that AAMC changed the rules so that they could avoid litigation, not the schools. AAMC instead put forth suggestions that each school can decide to enforce OR ignore OR make their own rules. There is no standard which is why I don't believe schools can sue schools for not know their individual rules. The new suggestions definitely make the process stranger that's for sure.