[Tasmanian Saint]

I honestly don't remember there being any options.. If there were, we were given two choices. Would you like Pizza, or Spagetti for dinner?

Well, what I mean is, when my kids are a bit older (ie, more capable) I can foresee days when I will feel like, 'hey, they've done their chores and that's fine, but I would really feel blessed if they'd help me out by doing the vacuuming' and I'd feel more blessed if they *chose* to do it rather than thinking everything I asked them to do was a command, yk? So if I were to teach them that 'no' is never an option then there would be no way for me to make a request of that nature. So I'm not doing that
Plus I think expecting kids to always jump as soon as you give an instruction is an invasion of personal boundaries, treating them as a robot instead of an individual. So having a 'command form', a 'immediate command form' and a 'request form' of communication allows the child autonomy while giving the parent the ability to pull rank when necessary.

In any case, with the example in the OP, the problem was not disobedience, it was miscommunication/ misunderstanding. Therefore the solution is not to threaten but to clarify. And then it's up to the parents, not grandma, to decide if they want to make the rule that all requests from authorities be treated as commands - and to teach this, not just expect the child to somehow *know*.