Like cracker says. You might start off not being cruel. But if you continue, then you start getting rougher and rougher. First it's water, then it's vinegar water, etc.. And maybe it is cruel to force your dog to be around other dogs when she isn't comfortable. Especially if there is a better way.
[EDIT: a watch me with a treat - takes a little bit of preparation,
Yes! Non aversives take time and patience and lots of proofing. They teach the dog what you want instead of scaring the dog and harming your relationship.
If this dog is doing this sort of thing often (which appears she does), then I think it's time to step back from competition for a few months and work on some issues.
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* About classes for my dogs. Three of my rescue dogs are quite nervous. Some things scare them more than others. I found a non aversive teacher that I like. I want my Lupe to take a class with her, but for some reason, Lupe is afraid of the building. Instead of forcing Lupe into the building, I'm tossing treats on the ground in front of the building.
Eventually I'll get her inside. But I'm not forcing the issue. We'll get there when she is ready. Once she is fairly comfortable with inside the building, we will sign up for class.
Lupe only weighs 35 pounds. I could easily pick her up or drag her inside. But why put her through that.