Snow Leopard on June 8th!?

According to the latest floating rumor, Snow Leopard might be released on June 8th. How did this rumor emerge?

1) Over the past years, Apple launched/announced new version of Mac OS X during the WWDC.
2) The WWDC always took place at the Moscone Center in San Francisco.
3) If Apple did not communicate about the forthcoming WWDC yet, some people noticed that the Moscone Center is reserved from June 6th to 12th.
4) If the WWDC starts on June 8th, it could well be announced during this time frame.
Last but not least, the fifth element remains hypothetical: Will Steve Jobs come to introduce the new MAc OS X?