My suggestion would be zero tolerance, which they're at now, but the fines need to be more forceful. I look to Australia, where it's nothing to have a $100,000 fine for having some sausage in your suitcase. You get a few of those fines out there and that certainly deters people from thinking they could sneak some stuff in.
To maintain the zero-tolerance policy and have some severe penalties for breaking the law, that's where they need to be.