I agree - we want the border sealed because of the illegal immigration problem.
but imagine if no one wanted to come here from Mexico - that we didn't have an immigration issue. and that border security was only about keeping out potential terrorists and criminals. should we not do it? should we eliminate all visas, passports, just make it wide open - since after all, the odds of catching someone is so low, why bother?
take a bunch of these "feel good" low odds measures all together, and I feel it makes a difference.
The difference is that securing the border does not infringe or erode any constitutional freedoms - random searches do.
The problem with this measure is that is both futile and infringes on constitutional freedoms. The futility and ineffectiveness of the plan wouldn't be that big of a deal if were more friendly to the constitution. And for what it's worth, the constitutional issues wouldn't be as big of deal if it were a very effective approach.
This approach however does nothing but erode freedoms and inconvenience law abiding citizens.