Every time I see basic internet infrastructure experiencing issues, my default is to think about who is testing a new cyberweapon or censorship mechanism. BGP has been known as trust-reliant for a while.
edit: the point being, how to do it is not an issue. they're not in the position to do it. ...but if you were thinking of censorship or outright disruptive terrorism via BGP, you'd be looking for infiltrating network operator jobs, not developing an attack. the attacks themselves are trivial, well-documented, and often happen accidentally.
edit2: "sorry we broke the internet" http://seclists.org/nanog/1997/Apr/444