If they bust you with an unopened package, they will try to get you to admit that you ordered it. And here's where it gets tricky.
If you ordered from a police honeypot seller, they have some reason to think that you did order. So if you at first deny ordering, and later admit that you did, you've just admitted to lying to them. Penalties for that can be worse than ordering illegal drugs ;)
Denial of guilt is not considered lying. Otherwise, every contested guilty verdict would have a perjury charge attached. Just say no. Or say nothing. Or one word: lawyer.
Say nothing. I think you can stay quiet but if you talk and lie to FBI, you will be Martha Stewart. Totally unrelated to the original case and they can prove this very easily, 2 FBI agents with detailed notes vs you.
If you ordered from a police honeypot seller, they have some reason to think that you did order. So if you at first deny ordering, and later admit that you did, you've just admitted to lying to them. Penalties for that can be worse than ordering illegal drugs ;)