... thereby making any successful manipulation of the github key database (by the github people or by an attacker, as has happened before - google e.g. http://e

... thereby making any successful manipulation of the github key database (by the github people or by an attacker, as has happened before - google e.g. http://egorhomakov.com/ http://egorhomakov.com/ ) a successful penetration of YOUR system. Security and convenience unfortunately conflict often.