Mako sez, "Unhappy Birthday is a website/project commenting on the fact that the song "Happy Birthday To You" is under an actively enforced copyright held by Time Warner. The site offers tools and information to report unauthorized public performances of that work. If educating people and upholding the principle of copyright means risking a DoS of ASCAP's licensing enforcement infrastructure, that's a risk I'm willing to take."
The best way to stop infringement is to tell the authorities and the owners so that they can follow up and arrange for a license and for royalties to be paid. Licenses for Happy Birthday are controlled by ASCAP. While monetary royalties will be negligible for a single restaurant performance, it is the principle that is at stake.
If you have seen someone singing Happy Birthday in a restaurant, a park, or at a school, you should tell ASCAP so that they can arrange for a license. If you are an offender, you should apologize and offer to pay whatever is due – a nickel, a quarter, a dollar – whatever ASCAP demands.
There is an overwhelming amount of copyright infringement of Happy Birthday. Let's right the balance and tell ASCAP about every one of these violations!