Pro tip: those scanners probably don't work with passports, so a human must still eyeball your passport to verify that you're old enough.

They can probably just deny you service at that point.

	▲	kmoser a day ago \| parent [-]
		They can deny you service at any time, but it's unlikely they will do so if you present a valid ID, even if it's not machine-readable. Not every driver license can be easily scanned, so in that respect it's no different from a passport.