The problem with the CTAF now is that aircraft are supposed to broadcast if they think their operations will impact on the traffic operating into/out of the aerodrome. Frequently transitting aircraft don't broadcast and guess what... their operations did impact on other aircarft operations. Also you can have several differnt CTAF frequencies within a small area i.e 4 or 5 within 15/20 miles. In CTAF (R) the R I belive means that you have to have a radio to operate there.