My experience with a senior this year has been that most kids are excited about their first acceptance and will post about it on social media, but it doesn't seem to be a big topic of discussion (although I haven't heard about anyone being offended by the topic!) My DC just paid her enrollment deposit for next year and she dusted off her Facebook page for that announcement. She doesn't seem to know where other kids applied, but she knows where a few of her friends are going next year.
As for SAT/ACT scores, I think my daughter was so shocked by her good ACT score that she tweeted about it, but it's not something she would discuss in a normal conversation.
Unless you are one of the kids who didn't perform as well and doesn't want to talk about it. Social culture doesn't respect that or forces them to lie to look good.
I don't have a high achiever and it has not been a smooth ride through high school. Still, she sees no reason to lie about her applications or acceptances. She was genuinely happy for and proud of a friend who got into Harvard while she herself was applying to Big State Us.