A previous thread posed the question: "Why did The Black Watch have the front of their spats cut off square? Various versions have the distinctive spat design as a dishonor for breaking a hollow square at a certain battle, to an honor bestowed upon the regiment.
I think the final answer may come from the Osprey book on The Black Watch:
According to the book's historical research, " Some curious fables have been invented about the origin of the square-cut toe of the spats, but this was merely a tailor's device, to prevent the end from working to one side or another of the toe-cap" A simple answer, and maybe this answers an age-old question.