Now do you really think any legit drug king pin who has like slaves with a 3rd grade education by the hundreds who don't even know how to use a debit card. Do you think these laws are stopping them? The government is just pretending to stop criminals, we know they aren't. Even if they did truly cut the numbers so a person could only bring $100 across the border, the criminals would just buy an airfield shut it down to the public and claim it was closed to traffic generally and do cash drops on them once a month with planes loaded with cash.
While technically customs could come and search it, these criminals are one step ahead. They'll claim one plane that matches the description of another they own, is going to come from Medillin Colombia to some place in Missouri. At the same time, they will fly DOMESTICALLY a plane from Alabama, flying to a near by destination. Have the planes land at opposite airports where they should have landed and arrive at the time they opposite plane should have landed. Meaning that the domestic one gets searched as the suspected plane Colombian coke plane, while the coke/money plane doesn't get harassed at all because its coming from Alabama.