Having a fast dog who lines well can apparently develop a type of handling error in blinds that in my case has taken a long time to recognize.
Consider this common scenario: the blind begins with a relatively easy line for some distance, then reaches a factor -- such as a diversion or an obstacle -- that makes it likely the dog will veer off-line, possibly quite suddenly.
It would be nice to let the dog roll to see whether the dog's training keeps the dog on a straight line, and then blow the whistle the moment the dog begins to veer. But if the dog is faster than the handler's reaction time, the result may be that the dog goes an unacceptable distance in the wrong direction. For example, the dog may go around a keyhole or wooden log that the judges expect the dog to go thru or over, and the judges will disqualify the dog if the handler tries to call the dog back. Or the dog may go out of sight behind a mound or over a crest, and thus be considered out of control (ooc) and again be disqualified.
The obvious solution is to blow the whistle as the dog approaches the factor without waiting to see whether the dog will veer off. But that has several arguments against it. One is that extra whistles potentially reduce scoring. Another is that stopping a dog unnecessarily potentially reduces the dog's motivation for running blinds. And a third is that if the dog is always stopped in a particular context, such as just as the dog gets out of the water while crossing a point, the dog may learn to anticipate the whistle and begin popping in that context before the whistle occurs, on blinds and even on marks.
I'll address each of those concerns.
As to the concern about scoring, I've come to the conclusion that the risk of being disqualified for missing a keyhole or going ooc is a greater concern than the risk of losing a little on scoringfor extra whistles. Therefore, if that's the only concern, blow the whistle and give the dog the extra guidance needed to complete the blind without getting knocked out.
With respect to motivation, I think that's a concern that some trainers will take more into consideration than others. For me, it is very real. But for that same reason, many of my training and handling decisions are influenced by an effort to maximize the dog's motivation for the work. That gives me a savings account, so to speak, especially with a dog who has had years of training devoted to maximizing motivation. And I've come to the conclusion that the situation described is an appropriate time to make a withdrawal from that savings account, and blow the whistle even if, in a parallel universe, the dog would have gone straight without it.
That leaves the third concern: accidentally training the dog to pop by consistently blowing the whistle in certain contexts until the dog begins to anticipate those whistles and turns to look at the handler even if the whistle isn't blown, such as when running a mark.
For a dog who is not a consistently good liner, that might not be a problem, because the dog would not learn that any particular context or contexts are any more likely to trigger a whistle than any other situation. But if the only times the dog generally hears a whistle are a relatively small number of specific situations -- the top of a crest, just past a stand of trees, an angled approach to high cover -- then I think the risk is real that those situations might begin causing pops when marking, or on blinds before the handler wants to blow the whistle.
After much consideration, I have reluctantly reached the conclusion that the only solution to that problem is for the trainer to begin blowing the whistle even more often, including situations that do not include a factor, and even if the dog is not veering off line. Yes, it might result in a lower score. Yes, it might slightly lower the dog's motivation for blinds. But if it allows you to take more control when factors are in play, without the dog learning to pop in those contexts when you don't blow the whistle, especially in marks, that seems a fair price to pay.
So this is the conclusion I've come to: In planning how I'll run Laddie (a fast dog who lines well) on a blind with a factor in the distance, (a) I'll plan to anticipate Laddie's possible reaction to the factor by stopping him before he has a chance to react, so that I can give him extra guidance; and (b) to avoid having Laddie learn that such contexts especially predict a whistle, I'll stop him sometime before he reaches that factor, even if he is on a good line.
I don't know how similar either element of this approach is to more experienced trainers with similar dogs. It would be interesting to know.