While I understand why a school might do this, I expect there is little actual data to support their policy. Even if there were said data, I would still think it’s wrong to limit choices…strong students earn those choices.
Whose purpose does it serve to literally make a student attend somewhere they might not want to…or take a gap year or potentially just transfer after a semester or two? Nothing the HS can do about a student transferring at some point in the future.
Edited to add: And if the family signed something agreeing to these practices, it can and should be difficult to walk that back. Caveat emptor.