This would be a great idea. If no such map exists, it would be possible to create a crowdsourced project where everyone who does a withdrawal gets asked whether the ATM charged any fees, and also asks to switch on device location to report the location of the ATM.
Actually I am against an ATM map because I fear that regular Banks will check that map and start adding fees to their ATM. I think right now many ATM are free because is flying under the radar.
Could that happen or am I just worrying about nothing?