Ford has been sued for switching to a 2-piece lug nut design that features an aluminum cap. When exposed to the elements, the cap swells in the heat, cracks and delaminates, and corrodes from moisture.
This leaves owners and lessees who get flat tires often stranded on the roads without the ability for even tow truck drivers to remove the swollen lug nuts. This means a tow to the shop just to have the lug nuts removed and the tire replaced.
The two-piece capped lug nuts are cheaper than a one-piece stainless plug, but they look nice because of the cap. Most owners never think twice about the lug nut when buying a vehicle, only to be met with this headache down the road.