In Switzerland you can wear any kilt, day in, day out.

My wife and I will spend a month in Lugano, Switzerland every year. This year it will be for the 13th time in a kilt there, I think. No problems at all. Absolutely no need to follow strict rules either, regarding accessories. Just look decent.
And expect no custom checks at the Swiss border, other than you can be asked if you bring any weapons. Between EU-countries, like Holland, Belgium, Luxembourg, Germany and France there is no control at all.