For years now this has been a concern of gambler’s traveling with cash. And there are many horror stories of gamblers getting their cash seized. Once it happens you don’t have a chance to recover all the money. Even if you win in court the lawyers will get a cut of the money.
Oklahoma has been particularly bad. Along I-40 there, a main cross country route, the cops in every county you cross are looking to seize your cash.
I’m lousy with links so per the usual, if the link doesn’t work you can google it.