A dangerous game of "cosmic roulette"?

I watched a reply of A dangerous game of "cosmic roulette"? from CBS 60 Minutes on CBS This Morning during their story Detecting asteroids: How telescope could help locate dangerous objects before they strike Earth. Michio Kaku gave an interesting talk on these meteors. (http://www.cbsnews.com/video/watch/?id=50156579n) (http://www.cbsnews.com/8301-505263_162-57606346/detecting-asteroids-how-telescope-could-help-locate-dangerous-objects-before-they-strike-earth/)