How bad do your grades have to be for you to be rescinded?
So if you were accepted to a top school, like an ivy league, and have been getting good grades in the past (mostly As and maybe a B or 2), how bad would your grades for senior year have to be for you to get rescinded? If you end up getting 2Bs senior year would that be rescindable? Or would you only get rescinded if you started getting Cs and worse or mainly Bs.
Getting your acceptance rescinded is conducted on a case by case basis and from what you wrote, there is no indication anywhere that you would have your acceptance rescinded for getting a couple of Bs. I know someone whose acceptance was rescinded from a UC school but that person just "checked out" senior year and got a few Ds, ending her Sr.year with a 2.1-2.2 GPA something like that. They didn't appeal, they went to another public college closer to their home.
Here's an excellent CV article about the subject of rescinding college admissions written by a CV expert. I hope it's useful to you and good luck with your admissions journey.