Crossing a border several times to increase duty free allowance

Question

I'm not planning on doing this myself (I'm not in a geographical position to either), but I just thought about the idea, and I wonder what type of rules are in place to prevent it.

This question could easily be too broad (differ from country to country), so I'll just say the two countries involved are Norway and Sweden.

Bob, Elise and Camilla are Norwegians traveling to Sweden.

Product A is much cheaper in Sweden than in Norway. Toll regulations say each person can bring only one unit of product A back to Norway from Sweden without paying toll.

While in Sweden, Bob, Elise and Camilla buy 20 units of product A. When they are very near the Norwegian border, they stop somewhere.

1. Camilla gets out of the car, and keeps 18 units with her.
2. Bob and Elise bring two units across to Norway.
3. They stop very near the border, on the other side. Bob gives his unit to Elise and goes back to meet Camilla again in Sweden.
4. They repeat the process, driving back and forth like this, bringing one unit at a time, until all the units are in Norway. They then drive happily into the Norwegian sunset with their stock of product As.

What rules are in place to prevent this type of behavior?

I limited it to Norway (to prevent it from being too broad). But is there a generally prevalent way (rules, etc.) that governments around the world use in an attempt to make this behavior impossible or difficult?

One thing I can think of is that you could have a rule that each person can only bring one unit within a timespan of 24 hours. But how is that enforceable? How would they keep track of which individual has already brought what? And often, if you are within the duty free limit, you don't have to declare it. If they check you, you are only carrying one unit, which is legal. I guess they could have a rule that says even the duty free quota must be declared and linked to your passport in a computer system. Then they could have hefty fines for not declaring even the duty free quota coupled with random sweep checks. But what do they actually do?

Answer 1

To answer your question (and also limit the answer to entering Norway), Norwegian custom rules only allow you to make use of the duty free allowance once every 24 hour.

Quoting from Norwegian Custom's information page on the duty free allowance:

Hvis du er i utlandet kortere enn ett døgn: Ved utenlandsopphold på mindre enn ett døgn kan du én gang i løpet av 24 timer ta med deg alkohol- og tobakkskvoten hvis du kan dokumentere at du har betalt avgifter i et EØS-land. Du kan derfor ikke handle på tax-free.

Or my rough translation: If you stay abroad for less than one day (24 hours), you can once every 24 hours make use of your free alcohol and tobacco allowance if you can document that you have bought the items with duty in another EEA country. You can therefore not bring items bought tax-free.

Answer 2

Beyond that specific case, there are a number of rules that can be used to make sure duty-free allowances are difficult to abuse (not all of them might apply to any one country and some might be difficult to enforce):

• Time-based limit as already mentioned by others. Alternatively, the allowance can also be limited to one use "per trip" (the end of the trip being defined as the time you return to your usual place of residence).
• Allowances only apply for personal use. If Bob, Elise and Camilla really want to use 20 units of A for themselves then it could still be technically OK but if a car goes back and forth, customs agents might very well get suspicious and consider that they are likely to want to resell them. That's usually illegal, even if the total price is well under the threshold.
• Allowances are not that high, you could play games with clothing or food but big ticket items are out (a single mid-range computer or smartphone is often already over the limit by itself).
• Allowances are typically even lower for tobacco and alcohol, which are often highly taxed and attractive to smugglers.
• The duty-free allowance may be lower when entering by road rather than by air and/or sea (because open land borders lend themselves to a quick trip to buy something in the neighbouring country, whereas even a cheap flight is already much more of a hassle).
• The duty-free allowance may also be lower for cross-border workers, people living close to the border or working in international transport (because they can bring a few items every day without much inconvenience).

Regarding enforcement, many borders in Europe are quite "soft" (certainly compared to earlier times or other parts of the world) and you will often get waved through or walk through the green channel at airports without anybody talking to you or looking through your stuff. Customs agents rely on random searches or simply noticing that something seems odd (like a car showing up frequently) and, if it comes to that, they can ask you to prove you did not break the rule (the burden of proof is on you). Another way many people get caught is simply tips: from jealous neighbours, estranged spouses, competitors, etc. None of this is systematic but that's how it works for all customs rules including checking that travellers are not exceeding the allowance itself so any 24-hour limit would not be unusual in that respect.