Just recalling assemblies back in the 50's and 60's. Great emphasis was placed on overseas witness visitors wearing their national dress to the assembly sessions, often as a prelude to them appearing onstage to give their experiences from their respective countries.
I once sat next to a fella in full cowboy dress, apart from the gun.
Never saw anyone in Scottish dress though..
Some idea of attire here: https://www.youtube.com/watch?v=CxKVck7Ldck