Will Apple leak screen shots of iOS 7 prior to WWDC?

It seems quite likely that the iOS 7 leaks we've gotten so far came from Apple. Would they leak actual screen shots prior to WWDC or keep it a complete surprise? Have they leaked software changes in the past? Last year we had a slew of hardware leaks. This year so far nothing. Is this Cook making good on his promise to "double down" on security?