You know you pass when.. You're sick, unkempt, in a thrown-together outfit, without a scrap of makeup on, completely hoarse from said illness...
...you introduce yourself to an FTM coworker, tell him you saw him on the LGBTQIA board...
...and he just assumes you're 'somewhere in the [lgbt] group.'
Sorry, dude - your T-dar's malfunctioning a bit. ^_^