All still sales are supposed to be reported to the TTB. The TTB is going through the reported sales of known startup still makers and sending out a "form letter" letting purchasers know that the TTB is aware of their still purchase and that unless they have a permit to distill alcohol, they are likely breaking the law. They also cited the recent sting operation with cooperation between TTB and the FL alcohol bureau or whatever it's called that resulted in "X" amount of arrests.
We purchased our stills through Hillbilly Stills and got a letter last week from TTB. No problem for us, we are a registered and bonded distillery. But for others, this could be problematic. If the TTB would have done any homework,they would have known that I as the purchaser of said still am also owner of a registered TTB business.
Bottom line, if you are buying stills or parts to build a still from known still builders, and you do not have a permit to distill alcohol, you are taking a big chance that your little hobby may become a very expensive trip to a defense attorney.
ADI does not endorse hobby distilling without a proper TTB permits. Stay legal people.