> I mean, if you go into a jewelry store with a gun and declare that everything is free you can get everything for 100% off (probably just the one time, though).

Maybe not even that; they are obvious targets, and as such precautions are common.

http://articles.chicagotribune.com/2001-05-08/news/010508027...

> Can't do that with jewelry on Amazon.

You can try, once you learn where the fulfillment warehouse is.