Listened very keenly (probably for the first time) to the safety explanation yesterday. All I heard was just the reference to keeping your seat upright during Landing and Takeoff, with no further explanation as to what that really means and nothing like "don't use until we tell you it's ok". Incidentally, I checked the in-flight magazine and also that is similarly vague. So, certainly could be interpreted in a number of different ways as the OP points out.