I had a thought about this. Leia is characterised by jealousy when it comes to Willi; I wonder how far her hypocrisy goes? If she kept herself a virgin, she's a hypocrite for saying that Katie couldn't seduce anyone, and doubly so for the way she pimps out her employees. If she's not, then her treatment of Willi's disappearance is hypocrisy because she has also abandoned him. She can't keep accussing him of having left if she'd moved on, and if she hasn't moved on, well Katie's had more recent relationships than Leia, especially considering she'd bi. I think this is why I dislike her - Leia has a massive double standard either way in order to defend her version of the story, so she can be the victim and the only right person. Willi does admit he did wrong on many occasions and is trying to grow, so I'm much more sympathetic to a jerk trying to reform himself than someone who gets people to call her princess.
Also, rumours about Willi and Leia were rife - from the scene with Dana:
da "Do you know what the people said after you vanished?"
d "Mh?"
da "They said that you and Leia had a relationship and your parents found out and kicked you out."
scene af1489 with dssa
"You raise a brow."
scene af1490 with dssr
da "The rumors the people spread were brutal."
da "Leia broke more than just one nose..."
This kinda supports the idea that what Katie was threatening was something that Willi didn't want Leia to know. Dylan and Helen would have understood that Leia's depression/anorexia wasn't simplely from missing her twin as they nursed her. Of course, Katie could have seeded the rumours, but if we believe she didn't tell Dylan and Helen, and didn't tell 'her', then chances are she wasn't spreading rumours either. I'd guess the rumours were organic or from someone like Mon, who is openly hostile with reason, wondering why (dare I say it) she was dumped two ways on the same night.