They've been given some concessions on reliability grounds.
Mercedes is allowed to fire half of its cylinders (ie. 4 of its 8 cylinders) while drivers brake. This is effectively hot-blowing but at 50% of the potential maximum. Hot-blowing has been banned for all others.
Renault is allowed to open its throttle up to 50% while drivers brake. However, Renault engines cannot hot-blow. So Renault teams - including RBR - basically get to do what they've always done: cold blowing under braking.
Red Bull was using 45% beforehand, and the maximum is 50%? That harms only Lotus Renault itself, who were using 90% ot these cold blows. FIA failed... again.
I suggest we move this conversation to the British GP thread which is where we will see the impact, or the general 2011 season thread for the overall picture.