This warranty issue is just where the "low cost manufacturers" take advantage of those who spend little for a product and accept what they get.

Let's suppose I drive a Kia vehicle (I chose that because it is reasonably low cost and not American, European, Japanese or Chinese). It is in warranty and I have an issue with the vehicle that is covered by warranty. I can take the vehicle to any authorised dealer who can perform the work under warranty and has their costs covered by the factory. Regardless of whether I have ever used the services of that dealer. what may not be covered is any specific "dealer warranties" that are over and above the factory warranty - that will depend on the fine print of that additional warranty.

If I purchase a low cost Engine for this hobby, the dealer is most likely going to wear the costs of any warranty related issues and is highly unlikely to be covered by the factory. For this reason many dealers of those particular engines won't cover engines purchased from others (even if they are in a similar location). I know from personal experience that some of the "higher cost" products we use are covered for warranty by the factory and that the factory covers the fair cost of warranty work to the dealer.

Any manufacturer that refuses to cover a product simply because it has made a relatively short trip is a manufacturer that is saying "We don't think our product needs to work to allow us to take your money" IMHO.

It is a business cultural thing.

One culture thinks
"I want - You have - please give it to me"

The other culture thinks
"I want - You have - I shall EARN the right for you to give me some of it"

That second culture is the one who generally provides a quality product with a quality backup service - usually at a higher purchase price to cover the cost of doing it right. I have dealt with both business cultures and the second one is a far more satisfying one to deal with in the longer term and it doesn't just apply to our Engines - it applies very widely in life - ask any stockbroker.