When I've been Vodafone customer they've happily enforced a price increase at any time quite regularly whereas in the past o2 didn't. Let alone that they've decided to change my billing date several times just to confuse things. Note its at a specific time that it will happen rather than 30 days notice which is at least clear. No doubt the other networks have agreed in principle to follow the guidelines but they'll be plotting another way to extract the cash from their customers. Wait for the calls to CS coming out of inclusive minutes...
On the other hand, it might actually accelarate the move away from long contracts into sim-free purchases like the refresh offering. Either way, if you go PAYG the prices will increase as well so nobody is going to escape the rises. We have plenty of choice these days to move around so don't hesitate to do it if it works best for you.
