There have been a couple of threads, I believe, on the popular "Happy Birthday to You" song, and my impression has been that the original sisters who "composed" it allowed it to be used freely, and never made an issue of the ©. It was only when their heirs took over that it became an issue. (It has also been suggested that they were "assisted" in asserting their copyright when the became elderly and needed some income.)

Regardless of the accuracy of this all, it is apparent that "they" now have lawyers and have sued a number of people to obtain royalty payments. Most suits I've heard of were against "commercial uses" if one stretches the definitions a bit. This has led to a proliferation of "even worse than ..." substitute "traditions," most notably at food franchise places that cater to "family swill-trough" feeding of the multitudes.

The "alternate songs" I've heard recently at places like MacD's and Pizza Hut are especially annoying, despite their "teams" being apparently (sometimes) well coached and mostly knowing the words. (One "Italian Franchise" place even brought out a banjo for some poor kid. Quite possibly bugle salutes and drum rolls will appear somewhere soon, if not already.)

A couple of suits that received some publicity seemed to hing on whether the employees performed, and/or on whether it was permissible for the employees to "suggest" that the patron group might sing. It still probably is safe to sing that song for non-profit/non-commercial enjoyment(?) almost anywhere, although the odds shrink when the legal hawks circle about.

Of course, the same ambiguities arise with the "Hallelujah Chorus" corruption, if someone chooses to make a claim and assert a demand for royalties.

John