Well, the only one who's contacted me unbidden is No. 2, which was a check-in email. She handled it fine, but I didn't feel I needed it, was surprised, did not want to feel special or attended to, and can easily see where things could get messy. Clients could come to expect such behavior after a bad session, and be disappointed if it didn't come. Result, mess.

As for non-therapeutic stuff, no way.