@icarushector
If you say that from the novel, be it, otherwise it surely doesn't seem like it.
- For example if that was the case I'd expect the word of a butler to have no weight against the son of a noble, particularly to his father. It makes no sense that the evil kid is fine mistreating the daughter of a noble (who would tell that to her father the same night) but stops for someone who just bowed to him, which likely means a servant, or someone of lower stance than him.
- A butler that dances with a noble woman at a noble's party it's not what I'd call proper. Not to mention that like he saw the evil kid, people saw him kneeling at her to ask her for a dance. I'd expect a harsh punishment for overstepping his boundaries, particularly after he knelt in front of his lady in the middle of the room, showing that he is her subordinate and just danced with a noble girl.
- It's clear from the first pages that there are adults around. If any of them saw that scene of a noble girl being jealous over him and blushing, I doubt they would have done nothing and let them be. Particularly when such an event is usually attention-catching.
Hidden relationship happened in real life with stricter rules, and if MC managed to do those things in public, I don't see how hard it would be to keep their relationship hidden, particularly if they start being a bit more careful.