And that's the argument that would have to be decided in court. But with the conservative bias in judicial outcomes and the "guilty beyond reasonable doubt" prerequisite for determining felony status, I am not holding out much hope that anyone will actually see jail time for this. I don't even know if this would get to the point where there'd be a trial, to be honest.

People get unsolicited mail all the time, and as long as the sender paid their postage, the government typically doesn't give a shit.