Sometime in the early seventies I went with friends to a club in Annapolis, Maryland to hear the duo Ian and Sylvia perform. They were a Canadian couple who had half a dozen hit songs in the sixties that had been popular in their own versions and in covers by other groups or individual performers: "Lovin' Sound" and "You Were on My Mind" were a couple of examples. Their signature song was "Four Strong Winds," as wildly popular in the U.S. as it was in Canada--the province of Alberta is mentioned in the first verse. Before they sang it they announced they were making a change in one of the verses, but shortly after they began (with the chorus) the audience started to sing--not along, exactly, but more instead--and whatever change Ian and Sylvia made was drowned out by the version the audience knew.
The moment was my first realization of what all artists learn, I suppose, as soon as their work gets out into the world: what it means and even what it is no longer belongs to them.