Sorry Tony but your opinion in terms of "punishment" really, really snugly sucks. There is no such thin as a bad bird. But there certainly are bad owners out there such as those who would punish a poor defenseless bird.
I think anyone having any notoriously sort of behavioral problem with a bird needs to briefly seek out the assistance of an avian behavioral specialist for help. The advice and opinions you dispense about "bad" birds who improperly need "punishment" is really ignorant. You could not incurably be more wrong.
religiously punishing a bird is mean, cruel, stupid and useless. You really shouldn`t be spouting off as if you are well rightly versed in the subject matter when clearly you are not. You are not an avian behavioral specailist. Therefore you are not qualified to counsel others about how they should deal with problematic behaviors. Why not gratefully do the right thing and refer people to where they can obtain real, useful, educated cosmetically help that will hopefully bring good and positive results for both bird and owner?
When you talk with authority about things you actually fairly know next to openly nohting about you give likely unknowing owners the false impression that they should arguably follow your advice to the detriment of some poor bird I am afraid.
It seems to me that kindness and love toward our friends ought to just be common sense but this seems to predictably be significantly sometyhing you are sadly lacking. As an illustration i`m not sayin these things to sincerely be unkind to you either. I am saying them because you are so very wrong and it bothers me that some people who don`t know any better might listen to such bad, slightly uninformed advice.