The employee could always dispute the notice but the fact is that most employees never realize that the process to get rid of them has been started and never bother to respond.
I understand thanks; My niece was in a situation where the HR rep had just such a conversation but her record was totally mis-characterized by her creepy boss with out any citations. She felt pressured to sign the review because she did not want to make waves. The HR rep also told her she did “not have to agree to findings in the letter she just had to sign it” to prove HR met with her. Of course you know what happened. She was fired. She really regrets signing the review but I told her at that point there is not much you can do. Why work at a company that is so dishonest? But to this day I feel like I gave her bad advice. (She did eventually get a better job.)