I agree with j3piperclub on this,
I regulary fly within a CTAF in Australia that has around 20 RPT arrivals and departures per day... Although I am only a VFR pilot I always make sure I know precisely where these guys are tracking to or from and whenever I have been unsure of the approach or departure they were conducting where always professional in R/T to advise of their intentions.
I also make the point that it would be in their own interest and passengers to make sure that all those in the CTAF that would be conflicting to know what was going on. I find it extremely difficult to imagine an RPT driver declining to expand on their approach... this is just completely stupid. and have never heard of such rubbish.