For me it is in the worst methods; a great possibility in failing because the idea is to go to reduce, not kill (yes, the USA is another world but still) if they see you with a melee weapon I would not be surprised if they would knock you down with the taser. Then, there is the moral issue of how it would affect him (Nor is it something that I judge because I re-thought ctb by train).
I think that before trying that method I would throw myself into the sea with stones tied to my feet. I don't know how much easier it would be to go into a gang and get a replica of a pistol out of them while intimidating them.