There's a bit of paranoia about whether payWave/PayPass contactless payments technology is fully secure and some people are willing to disable those in their cards. This post and this post explain how to damage the antenna by punching a small hole in the card near its edge.
This alteration doesn't compromise other functions - the magnetic stripe, the chip, the signature, the embossed text all remain intact. There is slight chance that this shorts the antenna wires and this in turn causes the chip to malfunction but let's ignore this for a while.
The serious issue here is that it's actually an intentional card alteration. And alteration of payment media may formally deem it invalid. And even if there's some line in the regulations that it doesn't invalidate the card it can get bank personnel interested - if the cardholder ever gives them such card they may suspect fraudulent alteration and this can cause consequences.
Would such alteration deem the card invalid? What consequences should the cardholder expect?