Always fun to throw a snowball and watch the pooches search and wonder "where'd it go???"
Fun too is when they figure it out
Pretty funny, but in reality, not something you want to do with a hunting dog/retriever. You want to build confidence, and trust with your dog. If I send Tara to retrieve a bird and it gets away because it is wounded, it kills her, she gets flustered, and panics even, hurts her confidence. And there have been times I cast her in the direction where I think the bird is, and I'm wrong, and this is not good because she is trusting me to send her to where the bird is, and it is not there, not good in building trust.
A big part of training (which never ends), is doing simple retrieves to build confidences and trust with your dog. When I send her on a blind retrieve, she runs a straight line where I'm sending her, and when she finds the bird, that is a huge confidence/trust builder. If that confidence and trust is blown too many times, the dog will not listen to you any more. A hunting dog that lacks trust and confidence will not run a strait line, you send them, they go about 10 yards strait then start going where they want to go.