It's great they post that but it's just not true. I can see how that would scare away buyers.
There have been many posts on this.
Another anecdote: My brother bought is E7 from an unauthorized seller and LG is going through the process of replacing his panel due to burn in (even a year after his warranty is up).
Also don't forget that most unauthorized sellers are still sourcing the TVs through authorized channels and play the game of getting you an invoice from the authorized distributor since it matters to a lot of people.
Just ask the seller how they handle this. Most already have a process in place to satisfy customer demand.
Current TVs: 77" LG C9, 65" LG B7A, 55" TCL R625, 65” GT50 Plasma