That is a very good question about "handedness". I have no idea how or if it is true with frogs, but I have witnessed Old World Chameleons that show preference when sleeping. Some always have the left front foot first on the branch, others the right.

What I wonder about with toads is, is this truly a luring tactic or just a nervous recation, like the tip of a cat"s tail when hunting. I wonder only because in B. nebulifer literature states their diet in the wild is primarily coleoptera. Other than tiger beetles and caterpillar hunters, I am unsure how effective baiting would be.