Can't you wear underwear in a Scottish skirt?

According to custom, you can't wear underwear in a Scottish skirt.

Scottish short skirt, a traditional Scottish dress, originally included a wide shawl, which was connected with the short skirt, making it very inconvenient to cut down trees. Tom Rollinson suggested to the tailor that the kilt be split in two, and it was "born".

Scots believe that as early as 1692, local people wore short skirts sewn together by two pieces of wide cloth and wrapped around their waists, and Tom rawlinson's invention was obviously "pirated". There are also historical records that as early as 1624, the Scottish army used kilts as uniforms.