Unless the product is a knock-off or stolen,, it's all been bought from an authorised dealer!
Incorrect....here's how it's done.
A customer walks into a store and asks to demo a pair of speakers. After the demo, customer declares that the speakers are liked, but that customer desires a Bryston amp.
Dealer say's something like "sorry, don't carry Bryston, can sell you XXX instead."
Customer say's "No deal, it's either Bryston or no sale."
Now the dealer has a problem. The sale is important (it's been a bad month, and bills are due), so the dealer says "give me a few days to get the amp for you, and we have a deal." After the customer leaves, dealer calls friend in another state who is an authorized dealer, and explains the problem. Friend wants to help out, so he sends a unit out of inventory.
A few days later the customer walks in, pays for everything, and walks out happy. If dealer is smart, he'll open the box and pull the warrany card. Since Bryston is close to bulletproof, dealer feels safe in doing the transaction.
This happens more than you can imagine, and has been going on for almost as long as there has been a hi-fi industry.