I investigated this point in particular, and my research was funded by the Schulich School of Business. I looked at the consequences of a policy of banning the ATM surcharges, and the main result would be lower ATM density. The fee is higher for the bank member, so the fee is switched from the foreign users of the ATM to the bank's own members. That does not improve things, but is just a switching of behaviour.
On April 17th, 2007. See this statement in context.