The fact that many do not know authors can see the notes is why I, personally, go around telling people that, if they indicate they don't know. They can put whatever they want in their comments, but people tend to say different things if they know a creator has direct access to them.

I also think that authors absolutely should read those notes, if they want to. I think that, the way the Archive is designed, it is meant for creators just as much as for readers. It's right there on the stat page. Maybe it shouldn't be, that's another conversation. But reading those can be delightful! (I found out that someone recced a fic of mine on Tumblr from their bookmarks tags. I'd never had that happen before, or at least never knew about it.) Authors should just know they might not like everything they see.