Can anyone wear any tartan?

[O'Callaghan]

Balmoral tartan as worn by a piper.

To be exact, the Balmoral tartan may be worn by the Queen's piper as well as by members of the Royal family. Hopefully, that's who the gentleman would be in the picture?

Now I've followed the link in the previous post, I see that it is the very man himself, and your picture is one of the pictures there. Interestingly, the later pics show him in the Balmoral tartan, but the first few pictures show him in a different tartan, mostly blue and green. I don't think it's Black Watch, although the pictures aren't very clear. Anyone know what it is?