According to the Protocol against the Smuggling of Migrants by Land, Sea and

Air, supplementing the United Nations Convention against Transnational Organized

Crime (2000), "Smuggling of migrants" shall mean 'the procurement, in order to obtain,

directly or indirectly, a financial or other material benefit, of the illegal entry of a person into a State Party of which the person is not a national or a permanent resident' (Art. 3(a)). Smuggling of people is seen to involve a voluntary agreement, to which the smuggled person has been a party. Smuggling occurs when migrants, due to legal restrictions and lack of knowledge of legal channels, cannot freely move across borders. Therefore they pay a smuggler to help them to get across the border. In practise it may be hard to distinguish between smuggling and trafficking since the former may lead to the latter.