In regards to the Nick Knapp case....two comments...and based on observation and what I have heard and read...
--first, the issue hinged on the one statement that Nick's "risks were acceptable" per his team of cardiologists. (this is stated clearly in his lawsuit which can be found online)
BUT -- that's the gray area....acceptable to one person may not be acceptable to another -- so Northwestern deemed the risks not acceptable.
The Reggie Lewis case (the Boston Celtics' guard) is a perfect example...
Lewis found a team of well-known cardiologists who said that Lewis could play and was medically cleared because although there were risks, that the risks were acceptable...
The Celtics felt pressured, backed down and let Lewis play, just as Knapp & his family was suing and pressuring Northwestern to let him play.
Reggie Lewis died suddenly during a practice game...and then even worse...the Lewis family turned on the Celtics and sued them for doing the very thing that Reggie wanted the Celtics do -- to clear him to play!
So I think the courts would be wrong to force a school, such as Northwestern to accept the risks based on someone else's view of what's "acceptable".