In reply to Penguin egg the problem may be in this definition of Scottish music. The traditional music of the Highlands is indeed related to that of Ireland as are it's people (Celtic-Gaels). The music of the lowland areas of Scotland is more related to that of England as are most of it's people. (non-Celtic Saxon)
Guitar tunings have little to do with defining this traditional music as the guitar is a relatively new insturment in an ancient culture.
                        Obie