Some clan tartans are also worn as district tartans (or have been in the past). For example, the Montgomery clan tartan is also the Elgin district tartan. The Drummond of Perth clan tartan is also the Perthshire district tartan.

But, just because a clan and a district share the same name, does not mean that a tartan for one is ipso facto a tartan for the other.

In my opinion, the Cunningham clan tartan is worn to represent the clan of the name, not the place of the name. So when you wear it, you are proclaiming, "I belong to the Cunningham clan," not, "I come from the Cunningham region." Same thing with the Ross tartan -- it's meant to represent the clan, not the place.

This can be seen in several instances when a clan/family and a district of the same name have distinct tartans. For example, the Sutherland clan tartan is quite different from the Sutherland district tartan. They represent two different things; one the family, the other the place. There is a different tartan for the Dunbar clan and the Dunbar district. It is possible to be from Dunbar without being affiliated with the family.

There are instances of district tartans later being adopted by families of the name. But this is usually due to the fact that the family name originated in the district, and in the absence of a preexisting family tartan, the district tartan is used. For example, the Paisely tartan is worn by Paiselys and allied families. However, the tartan was and is a district tartan for the place named Paisely. It was later adopted by the family.

Many named Galloway wear the Galloway distrcit tartan because they bear the name (even though the name is recognized as a sept of the MacFarlane clan and they certainly would be justified in wearing the MacFarlane tartan). But the district tartan is often worn by the family because that is the region that gave rise to the surname. The tartan itself remains a district tartan, however, and represents the place first and foremost.

Since the Cunningham tartan is a clan tartan, and intended to represent the clan and be worn by those with affiliations to the clan; and since there is another appropriate district tartan for the region (Ayrshire), I don't think I would advocate wearing the Cunningham clan tartan as a district tartan.