I really disagree with clipping and if not done right can cripple a birds wing forever (my friends african grey cant even flap his poor wings because of a bad clipping before he came to her!!!) and most birds can still fly with their wings clipped, i have seen many injuries and deaths from a bird having their wings clipped, one ladys bird flew straight into her wall and broke his neck and died, another bird has broken bones because of a wing clip. 
Unless its a matter of aggression i never agree with wing clipping and then it would need to be done by an avian vet.
To me its not worth the risk of increasing the chance of injuries, as for making it easier to tame a bird with its wings clipped  

 i tamed my billy in a matter of months without clipping his wings and he would try and eat my face  

 an example, if someone tied your legs together it would only increase your chance of injury and make you frustrated! Think of how our poor birds would feel. Plus it is vital for them to build up the muscles in their wings when they are young or that can lead to further problems.