If you're looking for a lover to stay by your side for a long time, I think you should pay attention to red flags and abort ship.
But if you're just looking for a quick fvck toy, who the fvck cares about red flags. I mean, you're not crushing on her or anything, right? She's not your girlfriend or owes any loyalty to you, right? So in that case, I don't think what she does matters. If you notice red flags but you're not aiming for an LTR, but a quick pump and dump; disregard those red flags and keep moving forward.
BUT, if you want a SUCCESFUL LTR, drop the girls who have red flags ASAP. I guarantee you it wont work out. Cuz with those red flags, those are the ways she will act during the relationship.
You're wasting your time with a girl you know you have no chance with. I prefer to go after girls who I know have medium-high interest in me. I don't bother with girls who have low interest in me. It's just a waste of time to me. That's just me, though. I prefer to spend my time wisely with girls who actually like me.