Not every player has email, or even regular internet access. Wasn't there a big stink last year, when the application process was going, that a bunch of folks who "should" have been chosen weren't, because they didn't hear about the application deadline in time, because word was spreading around on the net and they weren't on it? :/
And yes, they may have stated their plans to pay folks after every round on the website, and changed the plan later - it's a fairly minor thing, compared to something like changing the payout values or the like. If they up and *didn't* pay out the winnings, now that I could see getting really pissed off about. This, it's minor in the grand scheme.
Just another instance of folks reading a statement of intent and calling it a "promise". I've seen it dozens of times on the net, especially with the massive-multiplayer online game crowd. Game dev states "we have no plans to do (something)", said something eventually happens, the Internet Hordes begin screaming "THEY PROMISED!!!" etc.
Relax! Chill. Breathe. That's better.