Power
Border patrol agents are given broad powers to stand between our nation and foreign soil. They have the power to cut down on shady criminal acts and drug smuggling. They protect people from predatory human traffickers and are one of our main lines of defense against terrorism. They're also certified to carry a weapon and use it when necessary.
Naturally, all of this power can be abused when not properly handled or respected. The U.S. Border Patrol isn't happy when its agents mishandle the power they've been granted in order to perform their duties. Agents are required to take sensitivity training, extensively study criminal law, and follow all rules listed by the Border Patrol. Wielding excessive power against people will get you written up or cost you the job.
Most agents can handle the pressure. However, there have been numerous corruption charges against border patrol agents. Between 2003 and 2011, more than a hundred agents were charged with corruption or abuse of power. The circumstances vary, but each involves an agent breaking the law—not really something you want in a law enforcement officer.
To prevent Border Patrol Agents from abusing their power, Congress passed the Anti-Border Corruption Act. This Act requires that agents undergo a lie detector test every five years. Customs officers are also still subject to background checks during the time of their employment.
Being a jerk may seem like a great way to maintain control, but it's a much better way to get yourself in trouble with two countries.