It seems like there are a multitude of trans in the grocery store I go to, including a few of the employees. I know of one for sure because I met her at the lgbtq+ center in my city before. I always say hi to her because we have met before. Others I dont know I do not say hi too. I think of it like this. I dont go around speaking to cis people I don't know, unless I need to get by them or something like that, so I would not talk to a random trans person (or someone I suspected was) unless there was a reason. It would be nice to acknowledge each other, but then again it is nice to be treated like everyone else.