I don't understand why everyone is so up in arms about banning DRS in the tunnel.
As I imagine it, the danger was not to do with the fact that the drivers would have to push an extra button whilst cornering, but more to do with the closing speed difference it would make. As has been seen so far during the season, the increase in speed between a car with DRS enabled, and one without can be massive, which could lead to drivers trying to overtake too early in the tunnel where there is not enough space, or else hit the car from behind. Recovery vehicle access in the tunnel is impossible, so a crash of this type would red flag proceedings for ages.
Also DRS was brought in the improve overtaking during the race, not to improve qualifying times. To be honest there is no "overtaking" during practice and qualifying, so I don't understand why they allow it at all at these times (other than to check downforce limits in places it is used during the race). It was never likely to be allowed in the tunnel during the race because of the above reason, so allowing it during practice/qually is pointless.