You're right, training is not always at the level it should beI beg to differ please...the most irritating mistakes I see are from "College Trained Professionals".
I know that too, I have also seen dozens of irritating mistakes like the one you describe (and worse!), made by "trained professionals", and we (printers, you and me) find them especially irritating cause they are made by professionals with a training, meaning people who should be competent and who should not make that kind of mistakes.
But, even though files from trained professionals are not always at the quality level that a printer can expect from a professional designer, my 18 years experience has shown to me that files from non-trained non-professionals are always crap!!!
Training to XPress/InDesign/Illustrator and Photoshop is not always for designers, these tools are today parts of many other jobs: every printers in the World has (at least) a story of a web-designer believing that as he knows how to use Adobe's softwares he is then able to make a flyer or a poster, and he butchered the job with Photoshop.I had to explain that she was taught wrong.
I had a friend who was in a school to learn advertising. DTP and its softwares were quickly studied: not for a real design training to use them as production tools, but it as a side training, just an initiation to show to the students how the job is done from their mock-up to the poster at the back of buses. And when a student asked more questions about how really do DTP's job, the teacher said: "Launch Photoshop, create a new document in CMJN mode at 300 dpi, do something fine on the screen, then save as PDF and give the PDF to the printer, that is as simple as that".