Mayayana wrote:

Another convenient thing is software to check
the chip, to make sure you killed it. I looked
around and found that no one sells readers,
but then I discovered there's a free Android
app that can do it. A friend has an Android
phone. I downloaded the free app and held
the card under the phone to show the chip
ID number. I then drilled out the card and
checked again to make sure it was "dead".

So now the merchant knows you have a tampered with card. Good luck
buying high-ticket items with it.