I dont think it was a clearance to attack. The NATO officers would have asked that if there is a Pakistani military presence in a given area and Pakistan would have responded in negative..
if you have seen the video and audio conversation of 2 American A-10 pilots that engaged a British column in Iraq, they did ask if there were any friendly units in the area and then they started the attack after getting the negative, despite the fact that British firing distress flares and clear NATO/ British markings on their vehicles (same as the Pakistani flag over the post) the giggles of the pilots over the injured crumbing over and falling from burning vehicles is changed in to cries and sobbing when the operator tells them that they hit a British convey.
So here either the Americans knowingly or by mistake gave wrong coordinates, got the negative answer from Pakistani HQ and then gave the go ahead to their pilots to attack. But I don’t know how clear were they in their questions about any Pakistani check posts, also any Pakistani troops within 3 or 4 KM of their requested area would have been communicated to them as part of procedure so there is a chance that Americans would have asked about something too far away that the answer from Pakistani HQ had to be a no that they had nothing there in that area.
Despite all this what is troubling is
They continued to attack when they received the blue on blue and ceasefire requests.
They, then returned and attacked both posts and levelled them to the ground.
This only points towards disregard towards ceasefire requests and a premeditated attack with full knowledge of who actually were their target.
Should the American pilots have clarified with their HQ that the suspected locations appear to be well dug in positions that appear to be established posts with a flag and communication antennas and aerials? (not a characteristic of terrorists and that too on a hilltop with no civilian population nearby). Maybe not if they had the same average intellect & attitude of the pilots over Baghdad who decided that the Associated press reporter was a terrorist and his video camera a rocket launcher and on that bases they killed him all other civilains around him and then celebrated the death of the children in a van by saying wow look one went right through the windshield haha, now Julian Assuage faces a possible death penalty (over “espionage” ) if he is extradited to America due to leaking videos like these.
No wonder Pakistan army refused to be part of their investigation farce because of the past experiences and deliberately dragging the date to end of December so that the story dies down and they can mount the pressure again with the usual premix of Haqqani support allegations and end it with “do more” bickering. Maybe such actions will help in showing the democrats as tough guys for the up coming elections against the Republicans but this attitude is hardly going to help in their plan to exit from Afghanistan in next 2 years time