I have heard many opinions about whether a bird dog should stop at first scent, and whether a dog should be allowed to relocate on birds after stopping. I have flip-flopped on this issue and finally come down on the side of letting a dog self relocate after pointing, especially on birds that are prone to run out from under a point - and most of the species I hunt will do just that.
There are two reasons I like a dog to relocate himself and a couple of conditional statements.
First, I have always been more of a bird hunter than field trialer, and I want my dogs to be good producers of wild birds - but I want them broke steady to wing and shot. I believe that relocation on birds that are moving is one of the hallmarks of excellent bird work. But (here is the conditional statement) once the dog has the birds and I move in front to flush, I want him steady as a rock until sent on. This is consistent with good hunting and field trial practice, and shows that the dog can think for himself. Why shouldn't he? He certainly knows better than I do what the birds are doing.
Secondly, in a trial I want to show off my dog - I want him to display the bird savvy we have worked so hard on. Successful self relocation on birds that are running, when the dog can move as the birds move, and then pin and hold them is an awesome display of what a great bird dog can do. Some trialers - maybe the majority - want to dog to stop and not move until released by the handler. That's fine on planted birds that are less likely to run, but on wild birds, a relocation, if needed, will more likely produce a flush instead of a non-productive.
It takes a good dog and a lot of wild bird exposure and teamwork to make a dog that is classy, positive on self relocation, and then stands when the flush begins, and remains steady through the flush, shot, and fall. But it is sooo fine to see.