Originally Posted by
law dawg
If it's been dropped in the mail just that day then you're right - I can't prove it (of course it says that travelers are supposed to file the form with Customs at the port of entry or departure....). I'd would detain you long enough for questioning and notification to CBP. I'd ask things like what kind of questions were on the form, how many pages was it, etc. Things you should know if you really filled it out. Then I'd watch to see how nervous you were, other little tells. If I believed you, off you'd go. Ten minutes tops. If I didn't, off you'd go still but with me forwarding all the information I had to the appropriate agencies.
So by the same reasoning, you believe you're entitled to stop someone on the street, and demand that they prove they filed a tax return. If they can't produce it, then you could start grilling them with respect to questions designed to reveal whether or not they "really filled it out", like how many pages it was, what colour was it, what questions were on it, and if you were not satisfied, you'd be informing the IRS.
Funny, but I have never responded to any officer's questions with anything but questions of my own, or by noting that I'd rather take my chances with him than have my lawyer kick the s**t out of me later for being stupid enough to answer a cop's questions, and I've never been delayed by more than a few minutes, so I rather doubt you have the powers you imagine you do.