It's true there is little you can do when it comes to people not having the sense to look for a save button. Especially when it is a simple task they have done repeatedly in the past and should already know what do to based on past experiences.
But perhaps I can offer some advice that might help. I have seen a similar problem in the past whereby a dialog box was hidden under other windows. I believe in order to fix the issue I updated the video drivers and rebooted the PC, afterwards the dialog box opened on top of the windows like it was supposed to. If you can get the dialog box to show up on top of the other windows, your end user might clue in, the next step they need to do is, "save"
Another option is to update or change your print to PDF software. I use a free software call Foxit PDF, I will paste a link below. I hope this helps you in your quest. Although I do agree, you also need to train your tech support staff to train the end user how to perform the simple tasks, like looking for a save button for example. Once the end users are better trained, they will become more productive and less of a drain on your department. Good Luck