Yeah, what everyone else said. I just want to point out that this style of hose did not originate in the military. Like Woodsheal pointed out, it was very common in the 16th and 17th century to wear hose (called cadadh) cut and sewn from tartan cloth. And the most common, perhaps, was the simple red and black tartan "check" today referred to as "Rob Roy."

This is the origin of the diced hose (as well as Argyle hose), and they were not worn exclusively by the military. Modern knit diced and Argyle hose are simply meant to mimic the appearance of the tartan cadadh, cut and sewn on the bias.

I think that red and black hose will look good with just about any tartan in the modern color scheme, but look especially nice with tartans that are primarily dark green and blue (like your modern Lamont).

They are well suited to formal occasions, as has been pointed out, but I don't think you need to strictly limit yourself to formal wear.
Aye,
Matt