The case of the missing pens

There has been a lot written about how exactly two matching socks go into the wash only to have one return. I'm pretty sure it isn't a space / time continuum issue--but who knows for sure?
I, personally, have more of an issue with pens disappearing. At my current job, I fill in one Saturday a month at another location. There never seems to be pens there. When I brought it up to the manager of that location, the response was, "Yeah, pens are hard to come by. They always seem to disappear over the weekend."
Alright, so it isn't just me that has an issue with pens disappearing into thin air. Or perhaps they grow little arms and legs when we aren't watching and then scamper off. But where would a pen scamper off to?
Well, that was something I intended to find out a few years ago. TV directors use pens to make notes, mark scripts and so on. As the operations manager, I was tasked to make sure we had plenty of supplies on hand--including pens. However, no matter how many pens I bought, I seemed to always get complaints that we were running low. I got tired of my staff losing these pens!
So, I decided to become clever and install a poor man's GPS system into a box of pens. How did I do that? Well, I wrapped the end of each pen with red gaffer's tape. Gaffer's tape is like duct tape--it is pretty darn heavy duty stuff, so it wouldn't come off easily.
Within a week and a half, all the pens with the red taped ends were gone. Determined to find where they went, I scouted all over the station, but couldn't find any. I looked behind desks, under equipment-- everywhere. Though I found a few pens doing so, I never found the red taped pens.
Then one day after I got done directing our noon newscast, I went to lunch. After directing a live program, my mind tended to be running a million miles an hour--so going to lunch was often done by habit, without conscious thought of my physical actions.
When I got into my car, I went to put on my sun glasses--it was the first sunny day we had had in a couple of weeks. My glasses got stuck on something as I tried to don them and I realized I had placed a pen behind my ear. No problem--I'll just throw the pen into the storage compartment between the front seats.
Upon doing so, I noticed the compartment was full of pens--many with red taped ends.