I hadn't thought about rolling duct tape onto a Sharpie pen! That's brilliant... Duct tape is especially useful for taking care of cranky children or other members of your traveling party. I don't know if there is a purse that would be big enough to fit all the duct tape that I would need for one of my family Disney trips.
I would like to suggest that when tying crabby people up with duct tape and hiding them in the room it's important to leave yet another note for Mousekeeping that tells them that the muffled whining they are hearing from behind the bathroom door is just an ipod that has been left on and it's playing the song of your people. Hopefully that will get them to move along a little faster when servicing the room. It can be awkward when the police have to come to free people from their punishments .
~NinjaMom
I can see it now at the security checkpoints in the parks. "Please remove everything from your pockets, including duct tape and place it in the bin before walking through the metal detector".
