Interesting perspectives here. From a MacKay (grandmothers side) living in Scotland I can say my family are from the North and do regard themselves as a sept of MacDonald and are incredibly proud of such.

In addition the other branch of the family can trace back to the original planting of Ireland and ending up as a mixed Protestant / Catholic family so we have linkages there too.

Be very careful gents of trying to be cut and dried with our history, it never is that easy