Well, it just depends.. The customer's ads tend to be simple so it's not much work. As to OS X generated PDFs, you'd be correct in regards to Adobe, but it just depends on the program. And frankly, anyone making a PDF using the OS X option probably does not know enough to get a proper PDF (which is why I have issues). Like out customer I mention. I get RGB PDFs from Pages because like most clueless customers she'll place RGB PDFs and then just save out a PDF. That of course makes it RGB. Or I assume it does. I don't know Pages that well, but I keep getting RGB PDFs from her so what can I say?
InDesign you can export. QuarkXPress you can export, or make a PS or EPS file and distill. Illy, save a PDF, Photoshop, save a PDF, etc. But those are all options the program gives you. It's not directly written by the OS.
But say, you take a PS or EPS file that has embedded fonts. Open it in Preview and then save out a PDF
you'll get a RGB PDF that's been rasterized.
I hate Publisher! But only because people don't know how to use it. Most have no clue the difference between RGB and CMYK. As to your process, this is something I'd normally do, but we process our ads before they ever get into the newspaper document. So, I tend to just take care of it right there. Oh, I'll export an RGB PDF out of Publisher, but I convert it in Acrobat, then place it in ID.
No surprises on press day because I already know what it looks like. We're way behind the technology curve so we print seps which get pasted up then shot by camera, converted to film and then burned to plate. So, my seps have to be right from the get go. Fortunately, for us that period will be over in the next week as we are getting out of the printing business (but not the publishing business) and sending our papers to a printer from now on.
I'll be able to afford a little less anal retentiveness.
P.S. I've been in the newspaper business for 14 years, so I've gotten pretty good at ripping apart customer PDFs and repurposing the content. Pitstop, Acrobat, Illy, Photoshop and a few other tools really help. Ovis PDF-Recover is a great tool too as idiot customers sometimes like to pasword protect their PDFs. Ovis can crack them so I can work with them.