Whilst not sure about some of the 'new version kilts'; the traditional version is more than warm enough for any normal outdoor activity all year round. That includes winter hillwalking in snow and wet conditions UK & Scandinavia: so I doubt that there is any worry about cold weather. The kilt is also superb for river crossing-no need to draw a picture.

Regarding tights-I'd be more worried about bits that are best kept cool - overheating.

Too a decent pair of socks are warm, and if they get wet easily changed.

Having said all that, if a chap feels the cold and decides on a pair of tights/long drawers or whatever-really that should be his decision. Whilst a piper I know, one winter evening had to stand for ages doing nothing in a very windy/cold position, waiting for his one moment of glory: and he told me of borrowing a pair of tights, and what a great comfort they were on that occasion.

James