when i worked at tire kingdom, we'd ask the owner where the wheel lock was first, before just looking for it.

and like scott said, it might just be a matter of air pressure, stop at a gas station and make sure the air pressure is the same in all the tires. if it is, then go back and make them swap the front two tires (dismounting, and remounting if theyre directional, of course) and if it still does it....RAPE THEIR SISTERS!...errr...ask them to do an alignment czech.