The only valid reason we have to believe that it is coming before the end of June is because Motorola said it would be released in Q2. Q2 ends with the last day of June. At this point, anything beyond that is 100% rumor and speculation, and even that can change. I've seen the tutorial videos you're referring to. They've been posted throughout the forum several times. And actually, some of those tutorial videos first surface back in April, so again, basing anything off those is speculation as well.
We know the update is coming. The leaks, the app updates, and the tutorial videos all point to the fact that Motorola has been getting their ducks in a row for the release. But, as is evidenced by the fact that most of that started back in April, those things aren't an indicator of when the update will actually be released. The only real indicator we have is Motorola's release chart that says Q2. The next real indicator will be a soak test.