Just let me throw this out, how cautious do they really need to be with those measurements, I mean, it's not as if there aren't any safety tolerences built in, right.
If only the CM's would get on the same page, those Height Hittites (sounds better than Nazi. . .alliteration people) just want to make my little Butter Bean cry.
Don't tell me how to parent.
Bwahahahaha
If nothing else, the threads about cheatin' shoein' proves true my most cherished assumptions regarding parents. And Butter Bean? I'll have to remember that--much classier than Li'l Snotleigh
I'm not sure why the variance or how it happened, but IT DOES happen. 
Not saying it can't or doesn't happen, but I also don't think that it's a 'rule' that all cm's follow that if a child is 'close' they need to measure w/o footwear. Just my .02.
Sounds like something my daughter would do with her dad's assistance. How old was she at the time? I wonder if it was uncomfortable walking on granola bars all day!!