Walu,

Safaricom has had promotions, which ultimately were made permanent. Nothing stops Airtel from making this permanent.
What you are taking refuge in is the fact that Airtel told CCK that theirs is a promotion commencing 11th Jan 2011, without saying when it will end??

Let's look at it this way: You may fail to get KES 900 as dividend this year from Safaricom, but Airtel will have  made you earn it anyway, by making you call cheaply. It's a win-win situation for everyone, except the grumblers who, surprising cannot quantify how they are losing in the face of this "promotion".