I've been to a few Highland Games in Scotland, and I've been going to Games here in the States for 35 years, and I might point out that back in the 1970's there was less difference between Scottish and US Games than there is now.

Back then the US Games I attended were pretty much ONLY about the traditional Highland Games things. People walked about in traditional Highland Dress. There were the athletics, and Highland Dancing, and Piping, and perhaps sheep herding. Period. The merchants sold tradtional Highland Dress and ceramic Loch Ness Monsters and shortbread and little else.

All in all very much like the Games I've been to in Scotland in recent years.

For whatever reason, over the years Highland Games in the US have become more diffuse and might be called Highland/Irish/Celtic/Renaissance/Alternative Lifestyle festivals, almost a blending of a traditional Highland Games with a Ren Faire and the Seattle Folklife Festival perhaps.