Passengers checking their own bags strikes me as a huge security hole. Particularly if TSA is not properly screening all these checked bags. It shows the problem with too much emphasis on reaction to past events rather than real safety concerns.

When I worked at the airport, many years ago, pre-TSA, people would try and check all sorts of dangerous goods, such as camp stoves that had fuel in them. Without a human being who is aware of what items are dangerous in checked baggage and has the ability to notice that there is a likelihood of such items (such as by seeing a passenger leaving on a camping trip and asking whether they packed a camp stove) a lot of dangerous items could inadvertently get through.