Traditional dress doesn't neccessarily mean formal dress. One could make an argument that traditional dress for a Highland Games is anything but formal.

I always instruct people to dress for the occasion. Highland Games are outdoor events, day-long, held usually in a field somewhere, where you go to watch athletic competitions, hear live music, and do a bit of shopping.

Would you wear a tuxedo to such an occasion? No. And the Prince Charlie is the Highland Dress equivalent of a tuxedo.

I usually tell people who plan on wearing their kilts mostly at Highland Games and other outdoor festivals to wear a simple leather sporran, sensible shoes (you'll be on your feet most of the day), and a nice looking casual shirt. If you wanted to dress is up a bit, you can wear a tie with a tweed jacket and/or vest. But it shouldn't really need to be any more formal than that, unless (as Gilmore suggested) you are also attending a wedding at the Games or a similar function.

It is not that the Prince Charlie outfits don't look nice. They are just not the outfit for the occasion.

But I think Ron is on to something. People wear them to the Highland Games, in my opinion, likely because they spent all this money on a really nice looking Scottish outfit, so by-golley they are going to wear it to the Scottish Games!

As to the guy with his kilt on backwards -- maybe a rental?