Nevertheless, it is exactly what bother me that many engineers jump to "just do a GR&R" with no thought of what measurement system they are really working with. That this become a no-brainer answer without defining and understanding the variables of the measuring system at all.
The engineers are not wrong and you are not wrong. They are right in that you need to do a GR&R. You are right in that you don't "just" do one. You need to give it some thought so that it is conducted properly.
Let's talk about no-brainer answers.... I hear ya. When you are in the business of doing something and know it real well, you develop a sense that things are no-brainers. I have a lot of expertise in an industry that is considered a "black art" and there are lots of guys with experience that say they do things because "that's the way it's done, it's a no brainer." And yet, often I conduct an experiment and prove them wrong. So be careful with these type of statements. At first glance, a scale may SEEM like a no brainer. And I'm not looking at your scale, it's resolution, etc. I know my bathroom scale is pretty good at weighing me and my family. I'm less sure it's good for weighing my cat because my cats weight is small compared to the operating range of the scale. So I am more inclined to say "It's a no brainer" on a person, but I'm not willing to say it's effective on cats without testing it. Now, if this was the umpteenth scale you were calibrating and you have 20 studies in hand where it passes EASILY against the fluctuation and tolerance of your new situation, THAT's a no brainer. But if it's not, it MAY not be (I say with only knowing it IS a scale. Point is - be careful).
For example, i saw a measurement which has only one authorized operator in the whole plant. But for the sake of making up the three persons and three set of data, they just got someone who will not involve in the measurement (probably for the rest of their life) to take part in the GR&R.
This statement tells me there's a lack of knowledge of what GR&R is and why it is needed in your facility. Also, probably a lack of how to conduct the studies.
And as the guy above me (who's name I can't remember because I'm in the edit window and don't know how to find it, sorry) said - sometimes it is easier to just comply with the silly automotive requirement (they are there) than fight it. Not a bad path, as long as it isn't compromising actual quality.