A secured border will greatly assist in this "drug carriers" - but it takes secured borders, in many ways other than a barrier. We know it works where we have done so-problem is we left vast amounts wide open. 

As for a even bigger increase drugs crossing the border (I think that is what you mean?) we already have a very large problem, and one that is growing. 
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In 2015 DEA Drug Assessment-
Mexican drug traffickers remain most significant criminal drug threat to the United States
https://www.dea.gov/divisions/hq/2015/hq110415.shtml
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MAY 28, 2017
[...]Acting CBP Commissioner Kevin McAleenan said the amount of fentanyl, a synthetic opioid, seized at the U.S. border went from 2.8 pounds in 2013 to 440 pounds in 2016. McAleenan added that the amount of fentanyl seized this year has already surpassed the 2016 data ...
https://pjmedia.com/news-and-politics/2017/05/28/chairman-loosen-polygraph-requirements-to-speed-up-hiring-of-more-border-patrol/