The problem is it cost us little people money and lawyers to prove it.Totally agree. Their idea of clarifying the meaning of "in the business" offers zero clarity. In other words, stick to FTF cash deals only with people you know, and do the deal between 4 walls and a roof instead of out in an open parking lot, and nobody is the wiser. There would be no real proof you did anything and no way to track it. Same as it is now.
Now my next issue which is a question for lawyers: Does an online advertisement constitute proof of ownership and/or proof of possession of the item being advertised?
Lets say I post a random picture of a Lamborghini for sale on Craigslist for a million bucks. It doesn't prove that I am the owner, nor does it make me a car dealer. Furthermore, there is no proof that I ever owned the car. When someone comes to buy it, I say "sorry, it's already sold." Still no proof that I actually sold anything. At most, I could be accused of lying since I made it all up.
I just don't see how an online advertisement offers proof of anything. Merchants do that crap all the time. Advertise something, and then when you go to buy it, they're out of stock, which means the merchant does not own, nor is in possession of the item they are selling.
That being said, unless you sold directly to, or within sight of an ATF agent, how would they make a gun dealing charge stick based on an online advertisement?