When slogans go meta

The other day I saw a bus ad where the slogan was:

One of our unyielding principles: strong principles.

So odd. I guess it makes sense: in this company's set of principles, some are classed "unyielding"--they are never violated come what may--and some are merely classed "strong"--which to me suggests something weaker than unyielding. So the upshot, I guess, is that all principles are, at the very least, strongly held--and this will continue to be the case, come what may.

I have no idea what the ad was for.