Declaring illegal substances at customs - what would happen?
I've always wondered this. Occasionally I declare medicines, or wood carvings or whatever when going through customs. The point of asking you to declare these things is so that they can inspect and prevent say, bug-infested wood from entering New Zealand.
There's usually an amnesty box as well - if you realise at the last minute you have fruit, which you can't bring into New Zealand (just using NZ as an example here), you can dispose of it in their bins, no problem.
Not that I ever would - but, if someone came through and for some reason realised they had their illegal drugs stash on them - class A - something really illegal, and they declared it - would customs simply say "thanks for declaring that, we'll have to take that off you as it's illegal in this country" or would they arrest you?
EDIT: For the sake of argument as some countries will probably differ, let's assume the US for the accepted answer.
Best Answer
When you import coca candy from Bolivia into France, they just get confiscated. Hiding them is useless: custom dogs have an extremely sensitive nose.
I guess that this is the same for all products that are legal in your departure place but illegal in your destination place, like western women magazines into Iran.
I also guess that some products may raise attention of customs and you may undergo some questions from police about the reasons of your trip and why you brought a gun in your luggage or a laptop with an encrypted hard-disk. What happens next depends on your answers and whether you are already known to the police (either local or remote).
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Answer 2
Since its illegal to use class A drugs anywhere, you cannot use "prescription" as a defense. Moreover, even if you have a legal prescription for a drug that is illegal in the US - you may be charged with a crime. Any Californian with a green card knows that.
If you're lucky - you'll just get deported and will have some explaining to do at the point of origin when you're back there.
Just to point out the difference, the limitation on import of food and livestock is not because this kind of food or livestock is illegal (in NZ, per your example). You can have fruits in NZ. You just can't bring fruits from other countries. That is the difference between sanitary limitations and illegal substances trafficking.
Answer 3
Can't give a blanket statement about that. All depends on where you come from, where you're declaring, what you're declaring, your composure and behaviour, whether the officer(s) you're dealing with are in a good mood or not, etc. etc. etc.
I'd suspect the TSA goons in the US to be a lot less likely to just let you go than many a customs official in the EU, and in many African countries they'd probably wink and forget about it if you gave them some money (then again, those same guys might come back and throw you in prison as soon as you turn your back for attempted bribery, then keep the stuff for themselves).
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