Online banking hiccup
The BBC news story on the recent problems with the Cahoot online banking service also mentions an HCFB error where an e-mail was sent to 2,500 people in such a way that they could all see the addresses of the other recipients (CC rather than BCC).
What I find interesting was that this latter e-mail hiccup was regarded as a Data Protection Act issue and that HCFB was asked to compensate account holders.