Secret Button Sequence Bypasses iPhone Security
Found on Wired on Monday, 25 October 2010
A Brazilian iPhone customer demonstrates the quick method to circumvent an iPhone's passcode-protected lock screen: tap the "Emergency Call" button, then enter three pound signs, hit the green Call button and immediately press the Lock button.
An Apple spokeswoman contacted Wired.com with a response regarding the security flaw: "We're aware of this issue and we will deliver a fix to customers as part of the iOS 4.2 software update in November."
Seems Apple does not consider that bug important enough to issue a fix.