Not only is this an invasion of privacy, it also can have negative consequences in a world that is very intolerant of gender diversity.Transgender people can lose jobs, housing, friends, or even their lives when other people find out about their gender history.When a transgender person has transitioned and is living their life as their authentic self--that is their truth. Unfortunately, it can often feel disempowering for a transgender person to disclose to other people that they are transgender.Sometimes when other people learn a person is trans, they no longer see the person as a "real" man, woman, or person they are which, of course, is not the case.
Be careful about confidentiality, disclosure, and "outing."Some transgender people feel comfortable disclosing their gender history to other people, and some do not.
(It would be like a person looking around the room to "see" if there are any gay people.) You should assume that there may be transgender people at any gathering.