I suggested at the start, that the way Gaddafi tanks could avoid the new threat from the skies would be to get into the outskirts of the cities they were attacking because once in amongst the buildings and civilians, the allies would not be able to launch air attacks on them for fear of civilians getting hurt.
That seems to be what is happening in a couple of cities but the allies have taken a strategy of attacking the supply lines bringing new fuel and ammunition to the front, the idea being that denying the forward tanks these supplies will mean after a while they will simply have to be abandonned.
But I agree, it is not watertight, the Gaddafi regime will claim the allies are killing civilians, and the alliance and the rebels will say they are not. Where the truth is will be hard to guage. I suppose the sooner it is over the better.