You are making it sound like they are trembling about their loss of customers. I think the reality is, they aren't trembling at all at the moment. Things like this have been going on for years. I have been a member of Lloyds for some 19 years. The banks made 3 Billion last year from charges alone. A million pounds given back to the few potestors like us, is pretty much a drop in the ocean, as long as they can show that it is a lot of hassle to take them to court.
The media attention that the banks are recieving just now, will eventually fade away as it become a little too often, until the either, the law steps in (which is good for us) or the consumers stop actioning (which is bad for us).
I personally think, that the bank will come up with new ways to slow down our progress and hence restrict the number of people willing to do all the paperwork to claim their money back. Most people I talk too aren't bothered by it, which winds me up a bit.