These people are absolute idiots. Even if the pre-9/11 passivity continued, nobody could hijack a plane with a cup of hot coffee -- the perp can burn one or two people, and then he's got nothing.
Have you ever TASTED airline coffee? They could threaten me by trying to make me taste it....
/sarcasm
Makes me think of the part in Blazing Saddles, where the black Sheriff shows up in the town, they all draw guns on him. He draws his own gun, points it at his own head and states "Nobody move, or the n***** gets it." The townsfolk all back away and he gets to the sheriffs office when they're certain that the bad guy is serious about shooting the defensless sheriff.