A solid green kilt often (but not necessarily) connotes an Irishman; a saffron one always does.
I would dispute that. While widely accepted by Irish groups, there's historical evidence that it was used widely by Celts on the continent, before migration to the British Isles.
Please, by all means; dispute away. Please cite even one reputable reference for a saffron kilt (or any Irish kilt for that matter) prior to the 1880's, and your "historical evidence that it (the kilt) was used widely by Celts on the continent, before migration to the British Isles".