I certainly would not advocate anything that made the T uuncomfortable, or was totally out of line with their normal boundaries, but I do know many T's that adapt to the needs fo the client. Current T does not offer hugs or email contact to me, but I do know she has done both for at least one other client. She has kept me later however, when I was in a particularly bad space by the usual end time of our session. Generally, we end on time, but as need arises, that boundary is flexible. I have had T's call me initially blocking their cell phones or home numbers, but then grow lax on that as I don't contact then there without express permission each time. I know some clients would grow relentlessly obsessed with having alternate numbers. I have also encountered T's who were more apt to offer additional sessions to some clients but not others...
I also to try to have boundary discussions with T's very early on, as I tend to be hyper-aware of trying not to cross them. I need to know my boundaries so I don't accidentally mess up with them. i'm sure there are ones T's don't think about until they are crossed, or until they are asked about. I'm also pretty sure most clients are not as worried about it as I may be. When I say I advocate for fluid boundaries to meet the needs of the client, I also mean fluidity of when and how they are discussed or created. If something were to change with me, I would hope T would tighten or loosen her boundaries to best help me deal with whatever is going on (within her realm of comfort).
I would be worried about a T who randomly shifts boundaries without therapeutic necessity. I would also worry about a T who holds incredibly lax boundaries around one client and incredibly strict around another if it's not in the therapeutic best interest of both the clients and T to do so...