OY! or EEK! In my past life I was a repair technician. I'd HATE LIFE if that were done to me on a product. I suppose if the board is small enough in part count, it could be done with parts numbered in 10's or 100's, as in U10, R10, and U20, R20, etc.
So, are there any other GOTCHAS that I can't think up for doing it this for small one-of projects?
I thought the idea was kinda neat at first for a couple of reasons, but I mainly ditched it because I didn't want to spend the time to re-draw and reconnect everything on both the schematic and layout.
And, on my boards, my parts have select-able software ID addresses on the bus. Planning on going to have manufactured and I'm not sure how much more complex this would make the assembly. With the same annotation it is easy to state, populate only R1, R5, R7 on the first 10 boards, then R2, R3, and R6 on the next 10 boards.
I think I'm glad I already decided to NOT do it this way.