Tire Pull?

[PaHumBug]

So I took my truck to the doctor for it's yearly inspection. Had them rotate the tires and check the alignment while I'm there. It wasn't pulling or doing anything, just noticed a bit more tire wear on the front tires than the rear so I figured it wouldn't hurt to get it checked. So I picked it up and now it's pulling to the left and the steering wheel it 30 degrees to the right to keep it going straight. So I took it back and they said that it's probably "tire pull". They are going to swap the left and right side tires to see if it then will pull to the right, rather than putting it back on the alignment rack. Has anyone heard of tire pull before? I smell BS.