I wondered about this last months ago, and an AP article today gets me wondering again.

Smugglers in sunglasses and muscle shirts reclined on withering patches of grass in a tree-covered plaza, blending into clusters of migrants and offering them "safe" trips into the United States.

But on this sweltering day, there were no takers. None of the Mexicans hoping to reach the United States could pay the $3,000 the smugglers demanded to hide them in a car and drive them across the border, a trip that just weeks ago cost $2,000.

The sharp increase in smugglers' fees is due to the arrival of National Guard troops at the border and plans by Washington for even greater border security, all of which will make the sometimes deadly trip into the United States even more difficult and dangerous. The higher fees have convinced some to cancel plans to sneak into the United States, while others have decided to go it alone.

...Smugglers' fees jumped in 1994 after the U.S. sent more agents to what were then the busiest illegal crossing points along the Texas and California borders. The measures funneled migrants into the hostile Arizona desert, making smugglers even more valuable and transforming them from an underground network to a booming illegal industry.

In the past 12 years, the average price for helping migrants move north through the Arizona desert increased sixfold, from $300 in 1994 to $1,800.

Suddenly, smugglers are charging as much as $4,000, migrant rights activists say.

Deaths also have skyrocketed.

...Despite all the risks, Andres Flores, a 29-year-old construction worker who was deported to Tijuana from Los Angeles a week ago, planned to cross by himself through the desert near San Luis, Ariz.

Sitting in the central plaza in San Luis Rio Colorado, Flores said smugglers offered to guide him through the hills near San Diego for $2,000, a trek that previously cost about $1,200.

Note what I said before -- if the more elastic is coyote demand, the more likely border enforcement will be effective.