At all times the unlimited part of people in one way or another entered into the conflict to its majesty the Law. Feature of the conflict was someone’s aspiration «умыкнуть» on the party something over the resolved volume or in general in any way not resolved more often. 
Source
The classical historical example belongs to the 15th century BC when the Chinese princess in the hairdress delivered to the beloved to India silkworms. As a result of such simple action China lost monopoly for production of silk.
Many tried (and try still) to repeat the princess from Heavenly Empire and to leave customs with a nose. Hiding places in hair, clothes and on a body to customs are well-known long ago. Besides the special equipment helps to reveal them practically for 100 percent. And still attempts to take something on the body (or in it) proceed. It is necessary to be surprised only nonsenses of these people.
The most widespread place for a hiding place – long and fluffy hair. In them usually try to hide jewelry. In the majority of the countries it is accepted to bring without fail in the declaration all jewelry available at. However, in some countries there are eases. For example, in India employees of customs sometimes do not pay special attention to the wedding gold rings which being on hands and have not been brought in the declaration. Similar ease is available and in other countries. Provided that the ornaments being on you, not too expensive, it is a little of them, they are not brought in the register of the state historical values.
But there are examples when some persons try to conceal impudently from declaring a large amount of jeweler values. In 2005 attempt of the 46-year-old passenger to take in the twirled high hairdress more than thirty gold ornaments – rings, chains, earrings began sensation at the Sheremetyevo-2 airport. At personal inspection of things in the lady found 44 more gold illicit ornaments hidden in a bra. About this case the newspaper «Moscow Komsomol member» in detail wrote.
And here one more sensational case. Workers of a customs post of Strigino (the airport of Nizhny Novgorod) detained the passenger in which unprofitable chignon was more than one kg of gold in the form of jewelry. By the way, the Nizhny Novgorod customs is known for several such detentions. The last detention occurred in August, 2014 in export attempt from Russia of a gold coin of 1897 forbidden to export as cultural and historical value.
Repeatedly customs officers stopped attempts of export of values in clothes folds. And business not only that hiding places are easily found out by equipment, but also that it is impossible to copy precisely in clothes "firm" style of tailoring. Let’s tell, the expert in threads will measure a difference even by eye. And the difference can be not only in thickness of threads, but also in their shades. Podporoty and again sewn-up fabric "gives out" itself and other elements. Let’s say other trace from a sewing needle.
Attempts to take something in footwear too are well studied long ago. As a rule, smugglers self-educated persons tear off a sole and inside enclose a thin plastic bag. It is a package with money more often. But customs officers perfectly understand that, this or that footwear how becomes. Even on a glue smell from a sole can tell, what is glue brand. To replace glue with another to within what is used at footwear factory, – a task unreal.
As hiding places often use any subjects. It can be pens, felt-tip pens, hours, calculators, mobile phones … The jeweler values hidden in them too find without problems. It is usually enough simple to compare weight of two identical samples. The deviation will already cause suspicion. The real weight of subjects and things in which there is no hiding place, is well-known to customs officers on reference books. To "adjust" it to smugglers it is difficult. Besides, the equipment gives a definite answer, whether there are on the case traces from precious metal or not. The matter is that gold – very soft metal. And existence of traces will specify it that opened the mobile phone not only "regular" way (I will eat a back cover), but also unscrewed internal elements.
I do not argue, sometimes nevertheless customs officers deceive. But deceive extremely seldom. It not so ordinary people who are smothered by a toad from greed, and very high-class smugglers having access to the most perfect technologies also do. However nevertheless and they come across then. And they have a lot of time for thoughts on rigid plank beds.