When I was doing a ZA run I won a hex stick, since i had wrapping paper at the time, i wrapped it and forgot about it. Next week I did ZA I remembered the wrapped gift and unwrapped it to find its still there.
So with this I guess you can save those sticks if some idiot decides to kill all the frogs or sell it to someone.
I haven't checked if you open it while not in ZA, dunno if the item disapeers or is detectable by GMs. Also doesnt work with karazhan books because they are unique.Not sure about the legendary items in TK: The Eye .