I think the idea of starting in medias res based on a previous decision is very understandable. You aren’t taking away choice from the players; you’re making them stick to a choice they already made. Unless I’m misunderstanding what your saying, I think that you’re not trying to say freedom is wrong, but that choice has permanency. Flip flopping back and forth for a week before finally saying the polar opposite of what the GM has prepared is not expressing your character’s freedom so much as it is being a dick to the GM (unintentionally most of the time). I think that is a very understandable opinion to voice.