Bowling for the Truth

Here's a clip from the documentary film Bowling for Columbine.



Two questions:

1. To what degree, if any, was K-Mart responsible for the shooting at Columbine, and was it K-Mart's responsibility to stop selling ammunition?
2. How fair was Michale Moore's (the film's director - the heavy guy in the hat) ambush of K-Mart's Corporate Headquarters?