I had a long time T terminate me very unexpectedly. It was scary for me when I was in her office because I had no clue she was upset until I got there. My current T is mortified at how she handled the situation (which was different from yours).
On the other end of things I 1. Tend to know a lot about my therapists as I put together small details and I don’t forget much and 2. Am not above a good google search. One did become concerned I was stalking her. She was however very against me terminating with her. We talked about her concerns and if I had any kinds of plans for using all that I knew which I did not. She did say that if she found me using any of the information I had acquired (like going to her house or contacting friends/family) that it would be a severe breach of trust and we would have to discuss the ramifications.

Current T I know a TON about. Some he has disclosed but a lot was found with some very lucrative google searches. If I were to “come clean” and tell him everything I know... 1. He would understand my wanting to know BUT he would be concerned about how I decided to get the information. He would have preferred I ask him as he has always been very open and honest with me. 2. He would be shocked at how much I was able to put together which may rightfully cause some fear/concern... So... I can see him taking in that concern and changing the accessibility to some of that information overall... NOT as punishment to me just because I raised his awareness and others might not just be curious. 3. T and I... I don’t think it would be grounds for termination with him. I can see him insisting on talking about it in person. No matter how much it may (or may not) have angered or upset him he would not want me to feel ashamed about it (not proud of it either). I know we would talk about where the need to know so much about him came from and why I didn’t feel I could come to him with that need. I am sure there would be some stern moments but I think we would be OK in the end.