Read the terms in your warranty paperwork that you receive. It should be spelled out there.
Probably not completely. The consumer warranty statement tells what the
owner can and must do to get service, but probably does not identify where that service can be obtained,other than at an "authorized" dealer or service center. The only place that the manufacturer lists requirements on the dealer is in the dealer franchise agreement, and I know of no such RV franchise agreement that requires the dealer to service vehicle he did not sell. People assume this will be like a car dealership agreement, but it is not at all the same.
That said, it's not clear how widespread this problem is, but clearly it does happen from time to time. And when it does, it gets a lot of outraged attention on the internet, making it difficult to get an accurate picture of how many dealers actually do this.
The business of being placed on the tail end of the priority list is more widespread, but service at RV dealers is so slow I'm not sure it makes a lot of difference. We see numerous reports of 4-6 week delays in even routine repairs, for any and all customers!
I've found that many RV dealers are fairly sympathetic when a traveling RVer has a breakdown and try to help. That's one of the reasons that other work gets delayed - the shop takes in emergency jobs ahead of other work and there can be a lot of that during the busy summer season.