Well, the seller can tell the new owner the store he bought it from. that dealer should certainly be able to send the new owner, or the original owner a copy of the bill of sale..
And then the new owner would have it.
Personaly i think Bryston should have a registration process where the owner can register his/her item for warranty.
Byston certainly can handle that now?
Then once it is registered, the warranty would follow the item.
The current system depending on some slip of paper is BS, ANYONE can fake a reciept. Just make it up... Find a dealer who has been in business for the time and fake the damn reciept.
Obviously I am no big fan of having to keep some slip of paper or lose TWENTY years of warranty.
And yeah I bought mine from a registered dealer. My reciept looks like it came from a roadside diner. Nothing special in ANY way.