The only time I've ever had anyone say anything negative about me about wearing a kilt in Scotland was in the VisitScotland local office in Dumfries. That was taken care of in fairly short order and if I recall correctly the district MP got involved.

Who knows what some might have been thinking but they were never anything but pleasant and welcoming. In the pubs it's even better - they see the kilt and they notice. They hear the accent and they come up and start a conversation. Just wear it like you know what you are doing and don't do handstands or drool on people and you'll be fine.