Wow, people is throwing fast the new girl under the bus. I also believe that there's something weird about her, but not necessary bad.
Also regarding the thing that she's on the upper end of the banner... rememeber that along the very obvious arseholes we know and rightfuly hate, there's Taeyang and the ClassRep in there. Which okay, they're not nice at all, but Taeyang tried to mend things with Jonwoo and the ClassRep may say mean, ugly things that ultimately may help... in their own twisted way. Neither of them gives me the impression of full villains, arc villains maybe, but not big bads.
I dont think that the new girl is as bad as people think in here. My vote goes to she being the clingy, jealous type; but that any problem from her would be more from her current/former enviroment that her own fault.
Also, pretty sharp Jonwoo. He noticed mid-date that they were being followed. Nice.