And obviously that's a problem too, if that's what's going on there. Given the obvious danger in doing that, I find it a little hard to believe terrorists would be willingly sheltered by all that many groups in the area...but I could certainly see it happening.
Overall though, I'm not sure how much the reason the militants are freely running around the area actually matters when it comes to drone strikes. The fact is that they definitely are doing so, and Pakistan (either on the federal or tribal level) can't or won't do much of anything about it. If there is a better way than drones to take them out, I'd certainly be interested in hearing it...and so would our government, I'm sure.