R2D2 Postal Mailbox.

Lol, Genius. The thieves will catch on sooner or later, but hopefully it'll have saved you three sandwiches.

Now they'll probably just throw it in the garbage instead..

i i find that in the fridge, i would toss is ASAP.

I dig it. Thank god though that I don't have to apply a method like that at my office...I have very nice colleagues and in our fridge theres enough food for everyone.

Yum!

Janitors clean out the fridges of spoiled/expired food on Fridays at my workplace.

That won´t stop me from eating it.

I had a friend who kept on having her meals stolen. So she finally started putting chewed up gum in the sandwich. And voila...the moment she heard someone scream or gag she found the culprit...her boss. O_o

Great idea... I think.

But how do you tell if your sandwich really has been in the fridge too long?

Know what else would work well? A pharmaceutical grade stool softener in that sandwich. Yeah, go ahead & enjoy the Free Lunch, Mr. Poopie Pants.

I think I will just print up labels with something like "this sandwich is protected by a passive security device"...works for my car.

For every measure there is a counter-measure and eventually a counter-counter-measure.

If a protected sandwich gets stolen, you can leave an actual moldy sandwich in its place. The thief will think
"Heh, I'm not fooled by fake mold!" and chow down.

My Dad claimed he replaced the whiskey in his dorm room with kerosene and waited in the next room to hear the janitor sneak in for a wee dram. He never lost any again.

If your work requires you to pass random drug testing, you can grind up some legal poppy-seeds and mix with the sandwich. Apparently these give a false positive. For the ethically ambivalent, you could insert actual material (horse tranquilizers, BC leaf, etc).