What is the tradeoff in the scenario you described? You were enjoying time with your sister in law, you called a cookie a bitch, and then…? You weren’t having fun with your sister in law after that?
I think the cost of having to say something humiliating is at least equal to the cost of the cookie, so I want it for free. Of course I had fun with my sister in law, even if I rolled my eyes at the business. That's beside the point. Making you say this stuff is a tiny, petty act of domination. Say it or you don't get the cookie, or you look unfun. Anyway, it's the same argument people have been having forever about not wanting to say 'grande' at Starbucks. A war we won. And we will win this one.
Well, many would have done it the other way - had fun with the cookie and called the SIL a bitch :-)