That's nice. These are people I don't correspond with anyway, but hate to be rude. Some of their endless activities are taking up all my "friends' activities" column, though, and apparently there is no way to block individuals out of that column. (I did happen to notice that for one of the people I was going to dump, I was only one of two friends, so that one, I kept. She might have noticed. LOL)
No, if you delete someone from your list, or ignore their invite, that person is not notified. They may notice that your activity no longer shows up on their feeds, but there is no automatic notification that MedHelp sends to your ex-friend to tell them that they've been removed.