I have done this twice. I think it depends a lot on what your expectations are and how comfortable you are talking about things with others possibly being around.
My T is located in a downtown area of a city. We have done two walks. Because of there being others around, she felt more comfortable wearing masks, even though we were outside.
First time was awesome. I had low expectations and thought it would be a light session. I felt really connected, even asked her some questions about her, which I rarely do. There were people around, but not too many, and it didn’t feel too rushed.
The second one was awful. It was super busy, and felt really rushed. I think her timing was off, but I was also super emotional and felt like I couldn’t really tell her what was wrong. She was trying to be helpful and could tell she wasn’t able to be.
I won’t be doing another walk for quite a while, partly because the last time was such a bad experience and I would rather utilize my time better.