It is my understanding that the poor man's copyright does not hold water because it has failed in court. And if i read the copyright laws correctly (I'm not a lawyer) A registered copyright is required before you take someone to court anyway.
I have said on a previous thread that I try to deal with the copyright issue by requesting permission to perform directly from the composer (if known). Some times it is hard to figure out who wrote a song and sometimes it is hard to locate the writer but so far I've had real good luck. Eveyone i have either talked to or written has given me permission. Most have said how happy it made them to have someone want to do one of their songs. None have wanted monetary compensation. I am concerned about the songs i do from the 1920's, 30's and 40's. Usually the composer has passed away so I can't ask permission. And I do feel (as has been stated many times on mudcat) If no one performs these songs they will be lost to the mist of time.
I have a couple friends who have dealt with the copyright issue of the songs they recorded by directly paying the composers instead of paying ASCAP or BMI. Some of these composers are members of ASCAP or BMI. My friends chose to make payment that way because ASCAP and BMI are (I am told) notorious for not paying the smaller composers. The composers have not complained.
My last thought: I think for most of us it is a real drag that something so wondrous and good feeling as the performing of music has to get dragged through the mud of the court room by corporations and lawyers certainly more concerned with their own incomes than they are with the livelihood of any musicians other than the superstars. But it is the world we live in and we small fry musicians have got to figure out how to deal with it.