The Oyster cards use RFID technology, so the scanning antenna (the place where cards are swiped) actually provides power to the RFID chip: radio waves are induced through the red wire antenna to power the chip's transponder and transceiver. Therefore the red wire antenna will need to be kept exactly as it is found in the card to work, otherwise the power will simply be wrong and most likely burn out the chip.

Time to get the tracing paper out xD