We already know way more than we should about the next iPhone, and apparently the rumors just keep coming. BGR is reporting that AT&T has apparently told their employees that they'll be selling the new iPhone this June. More precisely beginning of June if you believe Jonathan Geller. Not much of a surprise there.
However, I don't think that's really how it went, since not many people at AT&T are briefed on such matter, knowing Apple. Most likely, employees are only told that a new handset is coming, and that's it. It probably wouldn't even take all the recent leaks and rumors to have most employees connect the dots. This likely resulted in some local store manager announcing to his team: "listen guys, we're getting the new iPhone next week or so, so nobody is goin' nowhere," hence the big titles that sound all official. In short, one rumor leads to another.