Kind of a dumb question, but I'm curious:
On my Sweet Georgia Brown "21st Century Toolbox" set of CDGs, on the CDG itself is stamped: 
"Federal Law Prohibits [copying yada yada]" 
then it says:
"Not For Public Performance Unless Played At Full Volume".
What's this supposed to mean?
I was thinking it was a SGB attempt at a joke, but I know most DVDs and CD's licenses are usually "for personal use only, not for public peformance".
So, I guess SGB is waiving that limitation on their license?
Then my question becomes: 
Is the licensing around other CDG's usually "not for Public Performance", like DVDs and CDs? IF so, are all the folks here that run a karaoke business using their copies/songs off CDGs in license violation? 
A quick Google I get this:
What is a "Public Performance"?
    Section 101 of the copyright law says that a performance is public if it is in a public place or if it is in any place if "a substantial number of persons outside of a normal circle of a family and its acquaintances" is gathered there.
(source: 
http://www.haverford.edu/av/copyright/pubperform.html)
So I guess karaoke in a bar is a public performance...
Me just being curious...