This is not common courtesy… And it probably won’t be any time soon. Most people will look at someone and decide how to talk to/about that person by what they see. And since the vast majority live their lives according to one of the two binary genders, this will rarely go wrong.
Don’t get me wrong, if someone tells me that they would like to be refer to in a specific way I take no issue in honoring that wish. But I’m probably not going to go ask everyone I meet how to address them.
