If any T is supportive of SI, they're a bad T. On the flip side, you shouldn't be "disciplined" for it either. My T is not okay with my SI. Partially because I go too deep now and it's really dangerous. But she doesn't make me feel guilty or ashamed. We talk it through. We have a plan in place for if I do feel like SI'ing.

One of my ex-Ts who I saw for 4 years, used to ask every week to see my SI. She asked every week for 2 years. Then one day she didn't ask to see it. I was devastated. I thought she stopped caring about me. That week I tried to kill myself. Didn't work. I saw her the next week. I refused to talk to her. Finally, she told me to leave if I wasn't going to talk to her. I broke down crying. I told her that I felt like she didn't care because she didn't ask to see it the week before. Her response was that she does care. She said the reason she didn't ask is because she trusted me to be careful with my cutting. She also said that she didn't want me to think that all she cared about was the SI. She cared about me as a whole, not just for the SI.