I think somebody needs to adjust their tinfoil hat! /kidding

Notice that silver "rounds" (bars, technically) that state content and fineness are no problem, on eBa* or anywhere else. Mr. Nothaus got into trouble primarily because he or others were trying to spend them, they had a face value on them (over twice the spot price at the time iirc) and, there was some confusion on the part of the intended recipients or holders whether or not the coins/rounds were actual government issue? See where I'm going with that? Did they look semi legal tenderish? Don't try this at home, kids.

Businesses and individuals are free to accept whatever they want, dollars are not mandatory, but the government reserves the right to "coin money" and don't step on their turf. That's why bars, rounds and commemoratives and medals and whatnot, those folks making them don't get thrown in jail.