Sometimes rules are broken because for the sake of convenience or or brevity, or to eliminate awkwardness, not out of laziness. This is how contractions came about, and they are almost acceptable in formal written language now, and certainly in lyrics. Someone probably had a real hissy-fit about "won't."

I, too admire precise language. My main objection when grammar is massacred in song or speech is that the message is unclear or even ludicrous. Mispronunciation galls me more. When I discovered that Walter Cronkite said "Feb-uary" instead of "February" I about cried because I always had taken pride in pronouncing my birth-month properly. My dictionary now lists his pronunciation as acceptable. I have decided to let go and let it be. After all, the flagbearer for Wednesday lost out to the one for Wenzday, didn't she? I shall survive.

Here's a convention that is dying a deserved, though lingering, death: the use of the pronouns "he" or "him" to signify any person in general. As a liturgical musician I am happy to see new lyrics artfully constructed with the new sensitivity, but I have difficulty with the published material we use in which "inclusive language" is intruding into very old music. I will NOT lead the people in singing "Good Christians All Rejoice." We white-wash our history that way--sort of Animal Farmish, don't you think? I know, what a paradox.

As artists we convey much more than perfect grammar can convey, using all the color, variety, flexibility, humor and inventiveness available to us in English. We to agree on the general rules, but the point is to be understood fully, not to be right.