Sent this to Google on Jan 22: "Could you please comment on whether this date for Google I/O 2014, published by http://portal.sanfrancisco.travel/calendar_public/
, is valid and legitimate? June 24-26, in Moscone."
That's the only place with any kind of dates related to Google I/O but because it's not officially from Google, we can't trust it.
Their response was basically wait and we'll let you know but nothing to announce at the time.