The scenario is: you’ve managed to receive ₩500,000,000 (~$337,265) at a Korean lottery (the catch is, only given in cash) which is delivered to you in two duffel bags. However will there be issues when returning back to the USA with that amount of money since it’s bundles of cash via foreign currency when the cap is $10,000 for undeclared amounts?
Adding onto this, the reason they press charges against the money instead of you is that, in the US, you would be innocent until proven guilty. They get around this by “charging the money” instead in which case it can be considered “guilty” until proven innocent.
What happens next is that you would have to sue them to prove the money/property innocent in court to get it back. Additionally you can’t sue and recover legal fees. So, if they only confiscated a few thousand dollars, you would likely spend more money trying to win in court than you would get awarded in the end.
It’s also worth noting, there’s an incentive for the TSA to tip off DEA agents to sieze the cash because the DEA will then share some of the money back to the TSA. Likewise for local/state police, even if they can’t sieze it under local laws, they can sieze it for some federal law and then the cash will be split between the law enforcement agency that siezed it and some federal agency.
More information here from a group that’s been fighting this in court (and winning some cases with the Supreme Court) here: https://ij.org/issues/private-property/civil-forfeiture/