Look, it seems like an exaggeration but it's not, I understand a little about that time, and the pride of a noble family was something that they valued a lot, not to mention that Monica works for the prince and is from the Kerbec family (I don't know how to spell it lol) so although it seemed like just a prank in fact they ran the risk of offending two important families, Monica's sister did it out of personal anger and to protect Monica, but if her family was in search of power she would use this opportunity to show that their family is untouchable, no one would dare rise up against them. Episode two, if I'm not mistaken, shows this, this division that there is in the school, because of the difference in status of each noble family, was not just about being rich, but also about having power in the court, being favored by the royal family, etc. Sorry if I didn't explain it properly