Well yes and no. If the "Highland attire" option is given or the "national attire" option is available then fair enough for those that qualify as being of that nation. However, if a Canadian, Russian, Mongolian, American, Scot or whatever citizen should choose to wear another nation's attire, then not only is he identifying that particular nation's national dress he is also identifying himself as a poser.
Well, that's a good point. I hadn't thought of it that way. Maybe the kilt is not at all appropriate for a non-Scot to wear on this particular occasion, being hosted by a multi-national group where national identity is important.