Comment Re:But (Score 3, Informative) 595
The problem is, you aren't "in the country" until Customs says you are. This is international law. The areas marked for international travel are technically an "embassy", not US soil. This allows the governments (plural, no matter where you are) to send you back where you came from without you actually legally "arriving". The movie "The Terminal" shows this concept very well. So, until Customs approves your arrival, you're not in the USA (and its "jurisdiction") and the US Constitution does not apply. The same goes for other countries as well.
So, you can refuse a search, but then again, they can refuse to let you into their country. The control is left to you and them (mostly them).
So, remember, whilst in an international terminal, whether airport or border crossing, you are in a place where only international law applies until that country says you are in their country. Until they say you are in their country, they have every right to search anything you bring with you, and every right to confiscate anything deemed as contraband, every right to send you back where you came from, and every right to use anything they found as evidence against you according to their country's laws after they say you are "in their country".
So, you can refuse a search, but then again, they can refuse to let you into their country. The control is left to you and them (mostly them).
So, remember, whilst in an international terminal, whether airport or border crossing, you are in a place where only international law applies until that country says you are in their country. Until they say you are in their country, they have every right to search anything you bring with you, and every right to confiscate anything deemed as contraband, every right to send you back where you came from, and every right to use anything they found as evidence against you according to their country's laws after they say you are "in their country".