An MSNBC reporter recently received a real world lesson in why President Trump’s promised border wall is crucially important to stop illegal immigration along the U.S.-Mexico border.

A reporter covering prototypes of Trump’s proposed border wall taking shape near San Diego, when the interview was interrupted by a group of “migrants” hopping over the existing fence.

“What happened?” the reporter shouted as a group of agents on horseback move in to nab the border jumpers. “The people are crossing!”

“Almost on cue, a group of asylum-seekers, migrants not from Mexico, jumped over the existing fence to turn themselves in to border agents on horseback,” the reporter narrated.

“It’s like, a small group of three people jumped over in the middle of the day,” he told a border patrol agent he was interviewing. “There’s a girl there in a pink backpack. Can you explain to me what’s going on?”

The agent said it’s just another day at work fighting the never-ending battle to secure the nation’s southern border.

“This is the reality of every day border enforcement. The United States is still the draw, the ultimate draw, for people that have dire situations where they’re at,” the agent said.

“We’re going to continue to witness this. It plays out on a regular basis for us,” he said.

“And it did here just now,” the reporter replied.

Virtually every day the U.S. Customs and Border Protection issues media advisories detaining the unsuccessful efforts of smugglers to ferry people, drugs, weapons, money and other items across the border. Many more are successful.

But data shows Trump’s comments about cracking down on illegal immigration is already having a big impact. He pointed out in an interview with the Associated Press this spring that apprehensions along the southern border, an often used measure of illegal immigration, is at the lowest levels in 17 years, a statement Politifact confirmed is accurate.

“Experts have told us that Trump’s rhetoric has played a role in deterring illegal immigration, perhaps more so than his newly issued policies, which may take longer to implement on the ground,” Politifact reports.

Construction crews are currently erecting eight roughly 30-foot-tall prototypes for the president’s border wall in a remote section of the border near San Diego, where at least a half dozen illegal immigrants have been arrested while attempting to cross amid the construction, according to National Public Radio.

The prototypes currently include four made of solid concrete, four made of steel and concrete and one topped with spikes.

“Customs and Border Protection is paying $20 million to six construction companies from Mississippi, Maryland, Alabama, Texas and Arizona” to construct the models by the end of the month, after which CBP will evaluate them based on three criteria, NPR reports.

“We want a better barrier. One that is hard to scale, hard to penetrate and hard to tunnel under,” Roy Villareal, chief of the San Diego Border Patrol sector, told NPR. “We’re hoping innovation from private industry combined with our experience generates the next evolution of border security infrastructure.”