[quote name='paynus']you can hide lunch meat somewhere in the store...maybe in a game display case? a few days later the smell will keep everybody out of there.[/quote]
Now, I don't agree with any of this, but this is simply a personal fantasy of what I would do if I wanted revenge for what happened to you. I have NEVER done this nor do I advocate any of the following. That said...
To hell with lunchmeat. If you are going to do something like this, use seafood. In particular I HIGHLY recommend shrimp, because their size to smell potential is very low, meaning they give you a LOT of HORRIBLE smell/bang for your buck.
just get a bag of frozen shrimp, they can even be the tiniest ones, and strategically place them around the store in inconspicuous spots. Even better if you can get them into empty NEW game display boxes, because it will be next to impossible to determine where it is coming from unless they open every single game box.
And you can always go back and give them a 'refill' every month or two. Put a couple in the magazine rack, around the demo game machines, etc.
If you want to do the ABSOLUTE worst, get a 1 gallon (or smaller or larger, but must be glass) GLASS jar and put a few pieces of frozen chicken in it. Then pour some dairy product into it, either milk, or yougurt, or sour cream, etc. DO NOT FILL IT COMPLETELY. Fill it about 3/4 full or a little more so there is air in the jar. Then seal it TIGHT TIGHT TIGHT. Sneak it into the store and hide it somewhere that it will be able to 'ripen' for a month or longer without being noticed. Preferable somewhere warm and in sunlight, but really that only speeds the process up.
In a month or so, the food products will have gone so bad and the bacteria/cultures in them will have produced so much gas as a byproduct, that the glass will crack, spilling a liquid that smells so horrendous it will never, EVER come out or lose that smell.
The best places for placement would be in the ceiling (if the place has easily moved ceiling tiles) or behind a computer server or row of servers/computer rack. In a retail store, the closer you can get it to the checkout counter/employee area, the better.