I ship a leatherman (with knife blade of course) almost every where I go and have probably flown >50 times since 9/11. I always pack it in my check baggage and have never had an ounce of trouble. Based on my experience, I would highly doubt that you'd run into the slightest bit of trouble.

The only thing that would make me think twice is if they are worth a lot. I've never had luggage completey lost but it's shown up several days late many times (I'll get you American Airlines!!!!)