[mattkrause]

Definitely.

It's a very common error and it should be easy to catch but....I've even seen a study that treated individual slices of an MRI as independent, which is laughably wrong.

I think part of the problem is that the "analysts" are increasingly uninvolved in the data collection, and just treat it as a tuple of (X, y). If you thought about what they mean, even for a second, ("Oh, Mr. Smith is always an awful driver"), the problem is obvious.