Here's one group of people that don't like closed borders and barriers to trade:
A small flotilla of rafts fashioned from trailer tyres and stacked with sacks of corn floats by, in sight of customs officials. Their cargo is destined for Tecun Uman's bustling market, which overflows with crackers and bread made affordable by the recent depreciation of Mexico's peso against the Guatemalan quetzal. "It's illegal, but it's a job for these people," says Antonio Aguilar, the chief of Guatemala's national police in Tecun Uman. That is one reason why he leaves the 5,000 or so small-time smugglers in this area alone. Another, he admits, is that when one of his predecessors cracked down on smuggling, a mob burnt down the police station.
from The Economist