At the design shop where I worked for ten years, we had a design department, a type department (either pouring copy into comps which were designed using dummy text or updating cyclical documents which didn't need redesigning every quarter), and a pre-press department.
When a document was approved and ready to be sent to the printer, the pre-press department would save a copy of the file which was specifically meant for that process. They would do the trapping, purchase stock photos, create trim marks (for folders and business cards and such), create separate pages for fifth plates, and repaginate into printer's spreads. In your case, they'd use Sections and Numbering to give each page its own section
start (and thereby make the numbering stick). Then they'd
drag the pages around in InDesign to get the printer's spreads as you
Unless my print provider was doing my pre-press work for me, I would never assume they would do the printer's spreads. I would assume that was my responsibility, to ask them how they wanted the PDF set up and then give them a finished file. Obviously this is an instance of Your Mileage May Vary, since Scott has the complete opposite experience. :)
It's really not a huge trauma to rearrange pages for him. The fewer moving parts the printer has to deal with, the fewer chances for him to make a mistake.