That’s a big FAIL to the ‘benefit denial” device, and a full on total fail to the RFID anti theft that let us walk out of the supermarket with the bottle of scotch to which the device was attached. Before the black helicopters arrive, we had paid for it.
Not wishing to drive back to the pit of hell, I set about it with a dremel. It’s quite interesting: there’s an RFID device that is meant to trigger an alarm, and the whole thing fits over a bottle top to prevent you drinking the contents (Mmmmm…Contents). It works like this: the cap goes over, and the top bit is rotated against a ratchet- this tightens two steel cables around the bottle neck to hold it on.
Here’s the results of an autopsy:
If you’re trying this at home, the fastest way in would be to cut way the round protrusion in the grey bit, and remove the bits of the ratchet. This of course, presumes that like me, you’ve actually paid for the stuff. If not, then the fastest way in is to beat yourself about the head with a switched-on angle grinder.
[edit]
I have now realised why the RFID didn’t work: The whisky was in a tin. Which would act as fairly good electromagnetic shielding for the RFID chip. 10/10 for effort, 0/10 for thought on that ten.

Nice one.
I bought a DVD from Asda months ago and once home found they hadn’t removed the red plastic thingy that locks the case shut. Like you, a return to the shop just wasn’t worth the grief. After all, they would just say sorry and remove it for you. Time spent and fuel burnt would at least justify an additional free DVD of my choice but there was little chance of that. So it was that I spent the next 30 minutes prising the bugger out with a screwdriver. The plastic shrapnel was a little harder to remove from behind the eyelids.
Good job I’d got a spare case to replace the now well-chewed original.