I still don't see where government can seize cash because you're carrying $50 or more.
--Snip--
I don't think you can cite a law anywhere - unless you step into fascism or piracy - that allows government to legally seize your private paper dollars.
The government wasn't seizing the dishwasher's cash because he was carrying $50 or more. They seized the cash because he failed to declare that he was carrying more than $10,000 while leaving the country. There is a big difference.
You want a cite that allows Congress to stop you from leaving the country with items (including cash) if they wanted to? Try
Article I, Section 8, Clause 3 of the Constitution - Congress shall have the power to "regulate commerce with foreign nations", and the law Congress enacted regulating foreign commerce, requiring reporting if you leave the country with more than $10,000 -
31 U.S.C. 5316.
You may not like the law, but it has thus far passed constitutional muster in the Circuit Courts. And it's not a new law - it's been on the books in its current form since at least 1986, and in some form or another since at least 1970.
I agree, there is nothing unconstitutional about this law. I just don't like it, and wish we changed it, although I'm shooting at the entire class of laws that invoke administrative takings (through judicial review), without a trial or finding of guilt.