I think what I would look at is to enable an operation level UD.
This could then be set up like a regular automatic UD.
You would set an automatic batch job to run every ten minutes or so and set any operations to "PASS" where all the characteristics are closed and valuated, or where all the characteristics on a particular operation are set to skip. You might want to have a different UD code for the operations that have all skip characteristics. Maybe use the actual work SKIP as the UD code. This program would need to be written and set up.
This way, I believe that in QE51n, all the operations where all the characteristics are skipped, would show as with a green check mark indicating processing is complete, (or in this case not required).
Now. I don't have operation level UD's enabled in my system to test this and it's been a few years ago that I played with that functionality. But I think you'll see the operation valuation in the QE51n screen. Kind of like the inspection point valuations are shown. But please test in a sandbox before proposing it to anyone!
Craig