Do I understand it correctly that if small dozes of sugar could make a measurable change in nasal secretions, immune response, number of sneezes, etc., then the premise of this article would be wrong?

Or would you have an ad-hoc explanation e.g. that the patient is suppressing the sneezes to avoid social embarrassment? If yes, where exactly is the line between measurable things that patient can do for social reasons, and things that patient cannot do for social reasons? I think understanding this boundary could be useful (for example we would know which illness can be treated by social means and which can not).