The fears of the community are compounded by the fact that many families live in mixed-status households, where some members are living in the country legally and others aren't, creating fear of separation.
Seifert said a further buildup along the border would be bad both for businesses and the welfare of the communities.
The view from Washington
The Senate immigration overhaul bill passed only after being amended to include tough border security measures: Doubling the number of border patrol agents on the southern border to nearly 40,000, increasing fencing to 700 miles and deploying more technology.
In the Republican-controlled House, border security is being touted as a prerequisite before any undocumented immigrants are placed on a potential path to citizenship.
"I understand the issues our borders face and am committed to making sure the first thing that must be addressed with any immigration bill is strengthening and protecting the border," said Rep. John Carter, R-Texas, a member of the bipartisan House group working on a bill.
But some who study the border say the boundary with Mexico is as safe as it's ever been, and it doesn't make sense to flood the place with border agents.
"It sounds good and it looks good politically," to adds more agents, said Maureen Meyer, senior associate for Mexico and Central America at the Washington Office on Latin America, or WOLA. "Calls for border security don't always reflect reality."
Currently, the border patrol is already double the size it was in 2005. As the agency grew, the number of illegal crossers apprehended decreased.
In 2005, each border agent -- on average -- apprehended 118 undocumented immigrants that year, according to data extrapolated by WOLA. Last year, that number fell to 19 apprehensions per agent.
If the border patrol is doubled in size again, how much further would that number fall? Would there be a lot of agents standing on the border doing nothing?
Not just a border issue
About 70 miles north of the Rio Grande Valley lies Brooks County, a community that has seen the cost of illegal immigration up close, even though it is not located on the border.
The county includes the town of Falfurrias, the site of the last border patrol checkpoint on Highway 281. Make it past the checkpoint, and a smuggler or migrant could be home free.
Most migrants try to avoid the checkpoint altogether, choosing instead to go around it by hiking deep into the vast tracts of ranch land.
But too often they become lost, or succumb to the unforgiving heat and die.
In 2012, 129 bodies of migrants were found in Brooks County. At least 42 have been found so far this year -- 11 in the past two weeks.
It can cost the county nearly $2,000 to pick up a body, transport it and perform an autopsy. The county is also burdened with the costs of sending its deputies to these scenes instead of patrolling the community. The counties that are right on the border have access to federal funds to offset law enforcement and other costs, but Brooks County does not.
The border "isn't secure, and I don't think they will ever secure it," Brooks County Judge Raul Ramirez said.
Still, Ramirez says that doubling the border patrol and prioritizing border security before immigration reform is not the answer.
"I think they don't get it. I don't think that's the solution," he said.
More agents will not stop determined migrants, but will simply drive up the price that a smuggler charges, he said. It also raises the likelihood that smugglers will choose riskier routes, meaning that even more people may die from exposure, he said.
What Ramirez would like to see is a deployment of current border agents to high-crossing areas, and a focus on catching drug traffickers.
What do border agents want?
The border patrol would appear to have the most to gain from an immigration bill with a tough security component. It would mean more money and more manpower.