Well Mr John McMahon, you wouldn't need to share your info with anybody. The idea would be to have enough people on board to actually cause the banking sector as a whole some pain, you wouldn't necessarily need to verify exactly how much the hit is, you'd just be aiming to make it as big as possible. And the bank wouldn't admit it of course, but they'd be feeling it. In any case, if a bank runs out of cash at their atms or their branches. there's no hiding that. Keep such pressure up over the long term, and you never know....

As for the "virtue signalling", that would be great as people are more likely to get on board once they see other people doing it.