If an officer of power does not have the power to demand something of you by specific letter of the law, but they ask for it anyway, are you within your rights to refuse and reasonably expect your continuing your current activity without impediment?
I can see officers just bringing up any old excuse (e.g. identity theft check, possible suspicion of person of interest) to coerce you into complying. One may find refusal is not worth the effort of reaffirming your rights in such a case, especially if you're genuinely not a criminal.