If a cis person meets a trans person and the trans person introduces themselves with a name that doesn’t match what appears to be their gender and they are working (meaning possibly their employer requires them to use birth name or something) what should that cis person do?
To generalize: in general, defer to the person’s judgement. If they’re giving their real name or their dead name or whatever, assume they did their own tradeoff calculations using more info than you have access to and just go with it, but also be willing to change if they decide to change their decision.