Would you say that your hypothetical event was perhaps a “private club” gathering? Here is the ASCAP license in that case: http://www.ascap.com/licensing/types/private-club.aspx the BMI FAQ: http://www.bmi.com/licensing Unless your block party was covered by the national news media, I don’t think you would have a problem. ;-)
Lol yeah I have since read up on the issue and understand the principle at work now. I have a habit to over-simplify things.