Originally Posted by
N1120A
Incorrect. You are conflating the NEXUS Land and NEXUS Air requirements. Since you don't do a written declaration with NEXUS Land, it is implied that you don't have anything to declare (though, Canadian citizens/residents are required to still write some sort of declaration). With NEXUS Air, you are subject to separate customs and immigration inspections. The immigration part doesn't usually involve human interaction, since such violations are much less likely to happen, but customs still technically does.
You are quite correct. My question and the answer were directly related to land crossings where there was no physical declaration (paper form). My comment was unclear in this. Since I rarely cross at other than land borders, I neglected this distinction.