I don't know what the answer to this problem is. You can't place ICC seals on empty trailers. Owner operators who have been sitting around a truckstop for a week or more waiting for a load will do about anything to put some money in their pockets. So, the temptation is there and the human cargo is also there.
Actually I do have an answer to this problem. Seal the border, put the military on the border, arrest and deport all illegals, and stop all government freebies to these people. That's the only way to stop this insanity. Fat chance of that happening.