The TSA has decided to allow knives, small bats, and other potentially dangerous items in the cabin of aircraft starting in April. This is an ill-conceived plan to alleviate work of TSA agents that will set up cabin crew and passengers as potential victims.
Sure, a terrorist couldn't force his way into the flight deck with a pocket knife or 'swiss-army' knife. But the blades could be sharpened or replaced with box-cutter knives that would not be noticed. You would then have the same weapons on board aircraft that were used on 9/11. They could start sacrificing cabin crew and passengers in hope of influencing the flight deck crew. Or at least being able to replicate in a smaller way the same event.
No one NEEDS a knife for a flight. Keep them in checked luggage.