It's an overlay, a satellite image of an area. I doubt anything can be illegal about it because your photoshopping out houses and details already. Now if it includes AREA 51 then I think you might have a problem.
I don't think they want to do it because it takes time to photoshop all the details out of the overlay and I know all about having to design a course for a company. They want it faster than you can pretty much do it and if you can't do it in the time they give you they pretty much say screw you and get someone else. Can't crank it out in 2 weeks? Oh well i'll find someone else!