I don't get emails, but I have been prompted to endorse contacts when I add them, or sometimes when I log in.
I have received endorsements from people I don't work with (e.g., not in my field) or who I don't know well, and I've chosen not to let them appear on my profile. I wouldn't want to explain to a potential employer that the person endorsing my legal research skills is just a neighbor and not a former client.