There are indeed many cases where somebody has had money seized just because you have it, claiming that it was taken by illegal means. Somehow they are able to keep it even without charging you with a crime. There's an alleged loophole in the 5th AmendmentI’m not sure about your other claims, but THAT is definitely true.
It’s amazing we live in a time where simply bringing a legitimate, large sum of cash to a seller for a piece of equipment is suspicious or unlawful.
It isn’t.
The government just wants their TAX cut out of that.
which allows it. https://www.justice.gov/criminal-afmls/file/794696/download