Little Sister: WHY ARE
YOU HERE?!
Roel/Sila: Bitch it was my invitation you got in with!
the younger sister doesn't strike me as the brightest in the bunch, and the taking of the dresses feels as much an ENTITLED as a mean-spirited pattern of action. A very small part of wonders if she even realized/was informed that the invitation was even Sila's. Or that Sila is engaged? Her being willfully ignorant of the drama in the family and just enjoying the opulent fruits of her parents' schemes would not surprise me in the least.
@unime tsundere princess who also knows they could NEVER get the hot holy night because celibate. Plus, there's plenty of reasons that Roel might have been flipping that Tsuntsun switch. She's not exactly a paragon of proper etiquette.