So you didn't shoplift and they'll have no proof so you'll be fine.

They always return to the scene of the crime

FYL OP. Same thing happened to me before. Did you maybe have something in your pocket/purse to set it off(not stolen)?

did you have a bullet necklace because whenever I wear mine it goes off

As a retail manager if they accuse you of theft and you didn't actually steal anything you can sue the store for libel (sp?)

Sometimes cell phones can set those off. On the other hand, sometimes people will steal something and then bring it to another location and try to do a no-receipt return for store credit.

( ͠° ͟ʖ ͡°)

The situation they're trying to prevent against is someone getting out of the store with stolen merchandise and then coming back to the same or a different location and returning the stolen stuff for money or store credit. Thieves will look in the parking lot or trash cans for a recent receipt, then go around the store and collect the items on the receipt so they can show it when the alarm goes off as they leave. That's why Loss Prevention really wants those anti-theft devices deactivated before they leave the store: so that if the alarm goes off as you're entering, they can be certain something's wrong. In practice, no one deactivates all of them, and they just wave you out the door as you leave, instead of calling you back to deactivate them. That's why accusing someone is a very bad idea.

I used to work retail. We've caught people who stole from other stores because our security sensors work on the same frequency or whatever they use

Its the perfect crime!