I think the entire notion of accuracy guarantees is amusing. I don't know why anybody pays any attention to it.
If you're talking Kimber, I agree.
If you're talking a company with a reputation for accurate rifles, it would mean something.
I hear you but I'm still with Bob. I guarantee I know people that couldn't shoot a 2" group with a rifle capable of beating the world accuracy record of any sort. Way too many variables to consider. Heck I shoot a couple pounds of powder and several hundred bullets finding 'The Load' when I'm working with a new rifle. I shoot plenty of 2" groups in the process to blame the rifle. And I bet I shoot more than 90% of people.