If you're the PIC and security give you grief, tell them that you're going to ask the Captain of the aircraft to keep it for you.
Hold the Leatherman in your left hand, ask your right hand if it would keep the Leatherman for safe keeping and then place the Leatherman in right hand.
Continue past security with Leatherman on person.
Important notes:
1. If you are left handed, it is important to reverse the order of handover.
2. This tip may be used for the conveyance of any other 'security' related items.
(I will not be responsible for any repercussions from using this advice!)