Interesting. I once had a minor incident in HNL when an AC agent had mistakenly assumed I was Canadian at check in in SYD. The DHS computer system therefore flagged me as ineligible to enter the US with an I94W. They had to correct the initial error - which was slightly involved - before I could go on my way.

Perhaps CLT uses the I94W for some internal purpose rather than its intended use, but from my experience it would seem that the DHS system will deny you entry if you are Canadian and trying to use the form.