Pure scare tatic, like they worried about any of us selling a part for 20 bucks, they will lokk at the big guys, but little guys they will leave alone, ever ebay sale I do has a Acme invoice, just like any other sale.
A little off topic, but somewhat interesting. About 4 years ago, I bought like $6K worth of Romac Balancers and Rollmaster vernier timing gear sets from Austriala where they are made. I got this year a notice from the South Carolina dept. of revenue a statement saying I need to pay sales tax on this, unless I was a businss with resale priviledges, well needless to say I am. Anyway I had to fill out some paperwork, send them some documantation, and that was it. I decided to call them anyway and get a feel for what prompted this, and you would be floored by what they told me. In over 40 states in the US, if you buy something mail order from out of state it is your obligation to report that purschase and pay the state sales taxes on those purschases, I couldn't control my laughter with lady on the phone when she told me that, how would the state or IRS even be able to tract every out of state mail order sale. It's rather obvious that it took them 4 years to catch up with me, and only because it went thru US customs I'm sure was why it was even tractable. The IRS and state tax collectors talk a big game, but they don't have the work force to back up their claims. Alot of folk don't know this but they actually made money on the stimilus deal as they got any back taxes folks owed that would be getting a stimilus check, that's why they are so eager to do it again, kinda funny how it works if you think about it.