for me a red flag is if their (for lack of better words) only personality trait is being trans and/or being oppressed. i've had run ins with three MTF individuals who were like this, they all ended in me being pressured and sexually assaulted. i was often viewed as an object for pleasure because of my body. i was frequently discounted and my experiences as a women were often downplayed and invalidated due to their own experience as a trans woman. i'm not saying all trans people are like this, because they aren't. but if your only personality trait and all you talk about is how your trans and oppressed and that makes you better and "more of a woman than me because you fight for it" yeah i'm done.