Protections for writers of recommend letters
On mathjobs.org letter writers can give an expiration date for their letters.
I have no idea what would happen if a disgruntled applicant took some sort of legal action to obtain a copy of those letters.
To the best of my understanding (I'm not a lawyer, etc.), in the U.S., in academic settings, there are no genuine protections for letter-writers. Rather, if/when everyone behaves civilly, there's simply no issue.
This is why I try to demur when asked to write letters in situations that make me uneasy, especially when I feel compelled to say &quot;I'm sorry, I'm not confident that I can write you a helpful letter. Perhaps someone else can do better.&quot;