But are "knowed" and "road" the best choices anyway? Could just be lazy versification.

Certain grammatical deviations simply reflect common usage among the folks the lyrics either originated with or are intended to represent. For instance, "ain't" ain't wrong within certain vernaculars, only when used in modern, formal English. But when grammar is twisted unnaturally--and not for obvious comic effect--it grates or at least distracts.

I can't suppress a snicker when I hear McCartney's "Live and Let Die": "in this ever-changing world in which we live in".

That said, I have to point out that the Olympics song doesn't necessarily contain a grammatical error. Consider: I believe in the power of "you and I". In this reading, "you and me" would be more grammatically questionable. Nevertheless, this interpretation, without preparation, is unlikely to occur to listeners, so I still consider it clumsy song versification, as glaring as the the Olympic torch.

English depends heavily on word order for proper interpretation, so the liberties taken in verse not infrequently lead to some comical referential ambituities: was it the cowboy or his horse that kissed the girl? I find these kinds of gaffes occur more frequently than disturbing grammatical errors; caveat songwritor.