The two situations I brought up were both cases where the student edited paragraphs or wrote the whole thing. Your situation is much less concerning.
The "waived rights" versus "but they offered to let me see it of their own free will" thing comes up a lot. Waived rights, you're correct, just means you can't demand to see the letter (since you normally do have the right to view your academic record by FERPA). If they send you the letter and you either ignore it until apps are done or read it right away, I doubt that anyone would hold you accountable/punish you.
But I think editing, especially with substantial content changes/additions, is starting to cross that grey area where you might get in trouble--grammar, less so, but I'm still not sure. One thing students could do instead is to say something like "You focused a lot on X, but could you highlight a little more of Y?" and have the letter writer fill in the words themselves. It would also sound more natural and in their style of writing
I would believe that. But not everyone agrees with her, (see my comments about the pre-med committee refusals to endorse). Again, I'm really not trying to be preachy. I know most people in these situations are put on the spot by the LOR writers and aren't trying to game the system--I was in that situation myself and had to avoid some hot water early on! I'm just relating what I've heard and seen happen so people can be careful with what they do.
EDIT: Found the
LizzyM post. She is clearly fine with it, and I'm not in a position to dispute that. But as with all opinions, take it for what it is: one opinion.