For me it's not even about realism. When the romance is so in-your-face i just don't want, say, Alistair starting to flirt out of nowhere. It's just awkward. Makes me thing of how in the DA2 you had to start a romance with Fenris to teach him how to read.
This happens even in real life if another person is shy you can get drunken kiss out of nowhere. ;-) In case of BG3 problem lies in getting tem all open at the same time. From choice perspective it is fine, but people might feel uncomfortable when game throw all at once. I think it should be done in a way that game tracks your flirts and approval rating and then NPC, wihom you triggered and has highest approval, gets the yellow mark. Currently I got only Astarion marked at tiefling's party and it was annoying.
