I pretty much agree with the OP, I have fed june beetles seasonally to species large enough to consume them for at least the past 15 years. Never had a single problem surface due to it either. June beetles are greatly relished by many toads and larger frogs and are abundant at certain times of the year. If you think a given frog will have trouble with them you can always break off the wing covers, but I have never found that necessary. After all beetles of varying sizes make up a significant portion of the diet of many frog and toad species in the wild.