Certainly, in light of the vigorous effort that was the Brigadoon industry since Sir Walter Scott onwards, merely asking (for the millionth number of times) this question is an indication of the complete ignorance of the factual information.
The clans first became social features that were common to the Gaelic-speaking Highlands and not the Lowlands. In the late medieval as well as early contemporary times, the common Lowland Scot would have been stunned if someone suggested that they had any connection with clansmen, who they would have considered to be dangerous, dirty barbarians.
The Lowlands were the most fertile areas which subsequently supported an even greater number of people than the highlands with mountainous terrain. It’s no coincidence that the majority of Scotland’s cities are situated in the Lowlands or along the eastern shoreline. Thus, most Scots during the 16th century didn’t have connection to any clan whatsoever. It was until the 19th century, following Sir Walter Scott’s romantic interpretation of clans, tartan and so on that the descendants from Lowland as well as Border clans began to redefine them as clans.
Some have also pointed out on the thread that the concept of a specific tartan pattern that is exclusive to those with a specific surname is also a common occurrence in the 19th century.
The tartans of the present however, with one exception, can also be considered 19th century inventions of the 19th century. I’ve been able to know that the sole tartan pattern (technically known as an asett) which can be shown to predate the ban on tartan during the 17th century was an old piece of cloth discovered in a bog in Culloden. It’s not clear which name the wearer and after it had been in a bog for half a century prior to the American War of Independence the shades had faded away to purple and mustard, therefore I would say it’s quite ugly. However, some people love it, and you can purchase it, or variants which usually substitute the mustard with a different colour in tourist shops.
A lot of stores selling tourist products in Scotland will say “If your surname is xxx, you belong to Clan yyy”. A moment of reflection will reveal that this isn’t true.
Consider, for instance, that the name you use is Simpson. For instance, the Brigadoon industry will inform that you are part of Clan Fraser. The reason is because Simpson refers to son of Simon and the name Simon was extremely popular within the Frasers. However, Simon is an angelic name that is used throughout all of the Christian world (and possibly also in as well in the Muslim world, although I can’t confirm this) as a name for a given which means there are thousands of descendents of the sons of Simon that have never been associated with Scotland or even the clan. In the same way you’ll be told that if you have the name Adamson you are part of the Clan Gordon. This is due to the fact that the name Adam was a common name in the Gordons.
If you’re named Taylor You will be told you are part of Clan Cameron. This is due to the fact that the family whose surname was changed as Taylor was part of the clan belonging to Clan Cameron. However, it is evident that the surname Taylor comes from the position of tailor. the surname could have been created independently wherever English (NB is not Gaelic) was used, and so the majority of Taylors are not related in blood to the Clan Cameron.
It is interesting to note that this modern-day kilt was created around the turn of the century in 18th century England through the (English) owner of an iron furnace. The Highland employees were wearing a heavy traditional dress with pleats that resembled kilts from the waist to the floor and a mantle that resembled an enormous shawl that covered the upper part of the body. He was thinking of cutting the upper part off and stitching the pleats of the lower portion together. Read more about the story of the Kilt on Wikipedia. Wikipedia
If you’d like to wear tartan or a kilt in another way it’s fine. Pick a set you like or order a custom kilt @Scottish Kilt, and then get into with the confidence that no one will pursue you. Also, make sure your kilt is of the correct length!