[michaelmrose]

If referring to a definite existing person who is physically present the default is to infer gender from a combination of physical attributes, name, and style of dress. This works about 99.9% of the time. For example it is almost always possible to tell that a person desires to present as a female even if they have some masculine attributes and or name and you can be nice and predict what they would prefer. The small percentage of times you get this wrong you just correct yourself and apologize and move on.

Being decent to people is important. Now if you are referring to a hypothetical person for example in documentation you can't misgender them because you are speaking hypothetically. At that point I think the choice is an aesthetic choice as opposed to a moral one. On cannot be harmed by the documentation using a different pronoun because the person was never speaking directly of you in the first place.