Not really. There are a couple people on here who I think I may have met before, but without their real name I can't be sure. If someone I actually knew messaged me it might cause my mind to flip sideways for a sec, but tbd for after the initial. It would really all depend on who it was and how we're acquainted.
Yes. I knew this person offline in a professional capacity for a few months. It was an incredibly surreal moment when I stumbled on their profile. I had never mentioned this website to them.