I was apprehensive about this technology, and then I saw the news reports about increased thefts occurring, evidently by people in search of these cards. Well, I do my best to secure my cards so that they're not stolen and I'm not overly worried about being hacked (see here), although I do realise that both of these are possibilities and of course I would be distressed if either happened to me. However, it seems to me the real issue with such cards for many people is literally closer to home, namely unauthorised use by other members of the household. It's not hard to envisage a situation where another person "borrows" the card, uses it and then returns it. Hopefully, it won't occur in our household, but many households and house-sharing arrangements are somewhat prone to events of this type.
Imagine the difficulty involved in disputing a single transaction (which occurred while the card was "borrowed"), where other legitimate transaction later (after the return of the card) have occurred!
I decided I would like to disable the feature. The CBA website tells me that this can't be done. I visited the bank, where it was confirmed that the feature couldn't be disabled (unless I physically damaged the particular part of the card), but a notation was placed on the file to the effect that, if a PayWave transaction occurs, I'll be notified.
The bank's action is better than nothing, but it seems to me that technology of this nature ought to be available on an "opt in" basis, and to my mind it's unsatisfactory that it's not even possible to "opt out".