Kansas' new casino law is that if you win $20,000 over the course of the year while losing $50,000 then you have to claim that you gained $20,000 when you report your taxes. Missouri does not have that law. So I don't get the argument that we're trying to drive Missourians here because we have less harsh sin taxes.
The only way they would know if you won more than $20,000 is if you won it on a slot machine or something that required them to go through a special process.
You don't show a players card or any ID when you return your chips for cash so they would have no way of tracking it otherwise.
*Fun Fact* ben ji's dad takes advantage of this, he will buy in for a couple hundred, play some hands then cash his chips out. He then goes and sits down at a new table and buys back in....To the casino it looks like he bought in for $200, lost all his money and bought back in for another $200 etc etc etc. In reality its the same $200 being recycled again and again... He does this to get more free comps from the casino and calls it "Recycling"