My T and pdoc are both on Facebook and LinkedIn. Their Facabook profile is private, so I can't see anything but their profile picture and friendlist.
I don't think either of them would accept a friend request from a client/patient. I'm almost certain T wouldn't. Not so sure about pdoc, but I think he also wouldn't.
I don't know if they would accept ex-clients on Facebook. I wouldn't dare to try, don't want a rejection.

I'm not really interesting in any ex-T. I once googled one and another one I looked up on LinkedIn because I was curious how long she was out of school when she became my T. Only a few months, no wonder she was useless to me. I don't miss any ex-T.

I think that if I would stop seeing my current T and pdoc, I probably would google them once in a while. Not sure how long I would do that. I don't know how long I would miss them. But to them this T-client relationship is totally different than it is to me. They won't miss me.