Yea they just throw it up on the machine dont take anything off.
i am with him.....it would be hard to get an accurate allignment without the wheels and tires on the vehicle..........the added weight of the wheels along with the weight of the vehicle on the suspension will cause an allignment to be way off if it was done with no wheels or tires on the vehicle........the suspension would be set up for no weight on it and when you add weight it will cause either extreme negative camber
our old mechanic made a special set of tools just for alligning vehicals that worked better than any 'computer' anyways, i have been beaten to the ground to NEVER get an allignment unless its absolutely positively no other way around it.
I just got new tires on the front, and they asked if I wanted an alignment, for $80! OUCH! The last 2 times I took the ranger in for my front pass tire going flat over and over, they did a free alignment and found nothing. These trucks are tough!