As balx says "After all its not illegal to make em or sell em".
But it is illegal to use them in most states so my opinion is if those that buy one get ripped off I don't care.
Also those using illegal methods will be getting more gold, paying no tax, risking losing gear when caught, but are usually making more money. We all know or should know dredging is illegal, so no sympathy from me.
They are lots of things that are legal to buy & sell, illegal to use, dredges , bongs, alcohol still just to name a few.