Hey hey hey, Goku managed to do it just fine without any consequence...well except when he did it that time with Cell.
The reason the man was arrested is because, without obtaining proper authority he decided to do the equivalent of make bomb jokes at the goddamn airport. it was there job to find potential threats and they found one, the man painted a target on himself and, because that's what security is supposed to do, they nabbed him. That being said, I think 50+ officers is overdoing it, and the security for the G20 was overkill. The man should face charges of 'mischief' or otherwise, be given a slap on the wrist, and everyone should make a big deal about it. They have to scare off people like him, the ones who want to dick around with security(for good intentions or bad). It causes a huge waste everyone's time and resources.
Pretty much, this is the face of world diplomacy, with the control of information they are free to accuse the world of things like protectionism while keeping their own internal appearance clean. Doesn't really matter what the world thinks of them.
But, chainsaws have no realistic use, they can only be used to murder people, gasoline? That 57 year old man was obviously in league with the anarchists.
Tasers need proper training, we have the potential to use it for some very effective non-lethal law enforcement, but officers simply aren't trained in its proper usage. They don't take the taser seriously, and that makes them a danger. That being said, I look forward to hearing of a proper conclusion of this.
That's because, given circumstances, they can be. If you're putting a butter knife to someone's eye that is definitely a potential weapon. I mean, of course it'd be silly if the guy had a butter knife and on a routine check a cop had seen it in the backseat and arrested him, but I've never seen an incident of that.