What's the definition of "can't"? Like if it's, You will absolutely never ever fart in front of me or it's over? I would agree it's unreasonable and untenable.
If "can't" is more like, Can you, please, try not to fart in front of me so often because at this point it seems like you're doing it on purpose?, that's just inconsiderate to not find another room to fart in.