I'm not digging through the thread to find it but Ayoubob already posted some examples of "decent" unauthorized overdraft charges (if I remember correctly it was something like 50p/day and capped at £5/month). If you do a search on google (like I did lastnight out of curiousity) you can find dozens (possible hundreds, I didn't dig into that far since I don't need a new bank) of banks that offer different (and better) options for unauthorized overdrafts...I found several banks that will deny the charges, I found several banks that capped the unauthorized overdraft charge at £20 - or below - for each month, I found several banks that offered a set interest rate fee (i.e. you pay 6% interest on however much your unauthorized overdraft is). It's easily accessible and readily available information for anyone who is serious. If unauthorized overdraft fees are a problem you experience habitually, I would definitely suggest you look around because there are much better options available.
Since I'm no longer with RBS, not overdrawn and have a new current account with Santander having it made it clear to them I do not wish to have any kind of overdraft facility, authorised or otherwise, no this is not something I "experience habitually", although this is frankly none of your business. However, since you are telling people to go and bank somewhere else, I thought you might have an idea of which banks offer a better deal. Not being able to name any yourself belies your contention that there are possibly hundreds. The fact is, if you wish to have the convenience of banking with a company that has many branches and cash machines doted abbout all over the place, which let's face it most people need, you are limited to a handful of big names like Lloyds, Barclays, RBS etc which charge these fees.
I sincerely hope you never have any kind of debt, whether it be an overdraft, a loan, mortgage or credit card because this ruling has implications for all of them.