There certainly is a group that promotes this addition. Were you asked before hand? Can you accept having a alignment simply because it has been awhile since your last one? What type of car? what type of suspension (upper or lower ball joint).
Myself I have done hundreds of ball joint replacements on BMW"S and never had to include in a alignment. In discussing this with other mechanics at tech school some guys always do them.
The shop doesn’t want you comming back with a tire wear problem and saying it was caused by the ball joint replacement.(none of mine came back).