I'm only posting here to help "advise" anyone reading this topic, thinking they might give this technique a try.
If you're reading this, you were searching about how to successfully commit fraud. You found this topic which describes a scenario of how one might do this.
DON'T DO IT.
For small items (e.g. under $100) it will probably work, but for any higher ticket items you will very likely be caught. How? These kinds of items have a special RFID tag embedded inside them. This isn't something stuck to the cabinet, but actually located inside the electronics. You won't be able to find it. This item is scanned to verify the serial number of the item. If you take a broken version and simply swap the casing part that has the model and serial #'s, they won't match the internal serial number. So, when the manufacturer receives the defective merchandise from the retailer and finds the discrepancy, the retailer will be notified and be denied credit for the merchandise. At this point, the retailer contacts the local authorities to report a crime, with your name and contact details on it. Let the hunt begin.
Now, you're thinking... OK, I'll try it and if it doesn't work then I'll just plead ignorant. No. Your very act of returning a swapped product like this constitutes grand larceny, which is a misdemeanor. Do you really want a criminal record? I highly doubt it.
If you want to take a risk on getting something for free, play the lottery. Committing larceny is simply not worth it. Good luck to you...