EL ALBERTO, MEXICO -- Gunshots ring out and sirens shriek, mixing with the ragged breath of muddy, panting humans. Suddenly, the full moon sweeping the ground like a searchlight reveals a disturbing scene: a group of illegal immigrants being handcuffed and led away by U.S. Border Patrol agents. But the U.S. border is about 400 miles from this rugged municipal park in Hidalgo state, a three-hour drive north of Mexico City. The spectacle unfolding here isn't an actual border crossing attempt but a live simulation-adventure that attempts to give participants a taste of what it's like for the thousands of...