Out of curiosity, what do you mean by "traditional urban legend approach that was popular on the shop floor"?
Here are a couple urban legends:
1. If the gage reads in the increments of the tolerance, it is good enough (e.g. if a caliper reads in .001" increments, you can use it for a .000 - .003" tolerance)
2. The micrometer is the best gage for anything. (Actually, it can be the
worst - you can get any answer you want if you crank it a little more. Is has chronic bias and gage pressure issues)
Neither of these - or similar urban legends - are supported by any MSA approach. But, they still live on...
I have been asking the same question you asked - "How do you answer if your gages are the right ones for the work you are doing"? If an auditor asked me this question, I wouldn't have a good answer.
To answer the question "How do you know if it is the correct gage for the job?" you provide a correctly prepared Gage R&R. To answer the question "How do you know the gage is still reading correctly?" you provide calibration information.
When we issue them out to the shop floor, we don't know how they are going to use them. We have ran across production checking an O.D. chamfer with the inside jaws of calipers, which is just crazy. This is what engineering listed on the control plan.
I agree, that approach would not likely fare well
if the question had been answered with a gage R&R of that approach with that dimension, I suspect.
We got nailed on our first TS audit for not calibrating our depth rods on calipers. Two Quality Managers got together and decided to remove all the depth rods and inside jaws from calipers because it's hard to get all three mechanisms to calibrate every year.

(first time I used this smilie...rightfully so...)
If the depth rods are used for shop floor measurements - especially if they were called out on the control plan - then they
need calibrated. If not, a note that they are not used in the calibration record, and training records that the operators have been told
not to use them, should be sufficient.
Wow. I really do not understand the approach they used to eliminate their "problem." It is not that hard, unless they are using the gages for can openers. And, how many hundreds of these calipers do you have to calibrate to make it an issue?
Do you have any suggestions:
On how to control how the gages are being used on the shop floor?
How to calibrate & use calipers without removing half the parts just to use the outside jaws?
Make sure the operators are trained on how to measure with the device.
Have the supervisors supervise the operators.
Last resort: make the operators pay for damaged gages.
I am right up there with the next guy on picking your battles, but this seems pretty extreme. I have seem some rude stuff - like people using the castings of a snap indicator to pound steel rule dies back into their backing boards...but...you really got me on this one!
