There are two main responses: some can’t wait to read my writeups of performances and tell other choir members to read them too. Others aren’t so keen on any potential source of publicity for the choir that isn’t under their control.
I have a policy of not reviewing performances I’ve taken part in and I also think of the potential reaction of people involved in the choir and of those who run the performance venue. In practice this means that my accounts are largely based around repertoire: what was new to me, difficulties I had in learning or performing it, how it compares to other things I’ve sung.
I will also now refrain from writing about a particular event, apart from noting that I took part in it, if I’m asked to do so on behalf of a choir that I sing in. Obviously I don’t want to put my place in the choir in jeopardy by saying anything that will give offence. On the other hand, it’s surely a good thing if choir members take time to reflect on what they’re asked to perform rather than singing it unthinkingly.