Oddly enough Woody Guthrie once used this as a copyright on one of his early recordings.
"This song is Copyrighted in U.S., under Seal of Copyright # 154085, for a period of 28 years, and anybody caught singin it without our permission, will be mighty good friends of ourn, cause we don't give a dern. Publish it. Write it. Sing it. Swing to it. Yodel it. We wrote it, that's all we wanted to do."Publisher peeved at political parody. - Jul. 26, 2004, CNN
This Land Isn't Your Land, EFF: Deep Links
Wired News: Sue You: This Song Is Our Song
Using Copyright to shut down satire