So in essence, you're pressurizing the 'system'. I completely understand what your describing, But that's not the same as calibrating a shock pump because that would imply your pump is reporting inaccurate values every time.
Instrument calibration is the process used to maintain instrument accuracy. The calibration process generally involves using the instrument to test samples of one or more known values called “calibrators.”
I'm pretty confident mtb suspensions aren't classified as calibrators.
Just nitpicking. I think your use of, "...know how to calibrate a shock pump..." is misleading.
No i don't because i honestly don't care. If you're so concerned about the few added grams then just take a shit before you head out on your ride. You'll save more weight than the difference between a 24mm and 30mm spindle.