An alignment job involves setting up the proper caster, camber, toe, and sometimes other steering and suspension angles.
Before an alignment is done, it is important to make sure all chassis parts are in good shape. If a bushing or suspension joint is worn, it will move more than the design of the parts allow for and that can cause the wheels to tilt at a different angle under certain conditions.
Toe In For Thrust Force
Many front-wheel drive vehicles have some toe-in built into the default alignment because then the engine drives the wheels, the forces naturally apply some toe-out as they work against the suspension and bushings.