Well it comes from....
Rumours in the 'industry' here about U2 coming late this year and supported by Pfinger are all over the place again, a report on Triple J, which is where October and the 3 cities comes from, and a friend from Brisbane telling me that Powderfinger were in the news this week for something unrelated up there and were asked about their plans for the year, they said something about wanting to fast forward to October, something big planned blah blah. So thats 3 in a week. Plus the u2tours website has dates for them playing Sth America at the end of October, usually part of the same leg....
But thats all I got. If they are doing 3+ shows in each city I'd say it's indoor, which is good.