Here is one of many pictures of the I94 available online:
http://amsterdam.usconsulate.gov/upl...aycBQ/I-94.JPG
At the top it says:
I-94 Arrival/Departure Record - Instructions
This form must be completed by all persons
except U.S. Citizens, returning resident aliens, aliens with immigrant visas, and Canadian
Citizens visiting or in transit.
(Emphasis added.)
Hence the confusion.