Paris Hilton’s plane evacuated over knife issue

I understand that security is a big topic when it comes to airlines these days, but honestly, this is just dumb – a Delta Airlines plane that was taking Paris Hilton and 203 other passengers from LAX to Hawaii was stopped before takeoff and evacuated due to one of the flight attendants discovering a large knife on board.

The knife was accidentally left behind by catering staff, which apparently was not a secret, but security decided to get everyone off the plane anyway, just in case.  Just in case of what, exactly?  It might have been smarter simply to get the knife off the plane instead of delaying everyone for an hour for no reason, but maybe that would have been a little too logical.