The banks must be tired of paying out to those of us (in our thousands) that have reclaimed bank charges, as they're finally accepting a test case in the courts.
Having worked for banks and knowing a little about their operations, I doubt very much that they'll be able to prove that they can justify the unauthorised overdraft charges. There's no way it costs them £30 a transaction, particularly the big banks which benefit from massive economies of sale and where everything is an automated computer transaction.
The banks will always win in the end though. They may lose their day in court and be forced to lower their penalty charges, and be forced to make refunds to customers, but they'll probably counter this by bringing an end to free banking in the UK.
Free banking is practically unheard of in Australia. There are a few accounts that don't make monthly account charges, however these tend to be dependant upon maintaining a certain balance in your account. For instance my main account is with the Bank of Queensland. If my balance remains above $2000 then I don't get charged, but if it drops below $2k at any time then I'll get charged a $4 monthly account fee.
I can imagine the likes of Barclays, HBOS and HSBC introducing something similar. Barclays have kind of already done this by stealth with their Barclays Additions account. If it's anything like the Barclays Additions account the monthly fee will be a lot more than $4 (£1.60)!