I used to have a dealers license. Then, I got a letter from the ATF advising me that beginning on a certain date that they could conduct without notice warrantless searches of my home, any time they wished to inventory any guns in my possession .
That same day I called ATF requesting shipping directions of my sales records, and my dealers license to ATF and that I no longer wanted to be a dealer.
The next day I shipped the box of documents. This was almost 40 years ago.