Here's a link to a picture of some recent fun in my microwave. It's the result of accidentally microwaving a Somerfield anti-theft tag for about half a second (which was all it took for it to spark like crazy, and me hit stop)
Dear Somerfield - I'm really not sure how much your 4 packs of lamb chops are worth to you, but I'm not convinced that it's a wonderfully responsible plan to add tags to the packaging that can't be microwaved.