Don't Do This To Your BART EZ Rider Card Answered
BART, Bay Area Rapid Transit, recently issued RFID-based fare cards called BART EZ Rider. If you look closely, you can see where the actual chip is embedded within the card. Like other similar cards, I assumed there was a wire antenna also embedded in a rough spiral around the chip.
The card didn't fit nicely on the outside of my Jimi wallet so I decided to cut a notch to make it fit better. While I didn't see any evidence of cutting the antenna, the card quit working. So, if you plan to chop your card, at least try the opposite side as mine!
Since the Jimi only fits four cards inside, and I carry five, next up, cutting apart my Discover card...