So you are saying that a person who makes the effort and pays the expense to go to a Knife show, buys 2-3 Busses (at full retail cost) with the intent to sell 1 or 2 at a profit to perhaps defray some of the cost of the trip, should be treated (and charged) the same as someone who buys 500 knives per year at 1/2 MSRP from Moteng or BRK?
Intent is a hard thing to prove. In the end, everyone who sold any knife on BF could be accused of being a dealer by that broad stroke.
To me the easier way would be to do what many states do to classify a person as a car dealer or not--count the sales. In Alabama, I believe that you are allowed to sell ten used cars per year as an individual. But to sell eleven, you need a business license, tax ID, etc, etc.