Can you eliminate a noise by just putting the car up on a lift?

[Huskymaniac]

I had this moderate knocking/rattling noise in my front end. It seemed to be worse at low speed over uneven bumps. It didn't go away when braking. My mechanic and his co-worker looked at the suspension components three times and couldn't find any issues with the usual suspects. When I had my tires changed over from snows to all-seasons and an oil change, I had him look again. He said he didn't see anything. When I drove the car home, I noticed the noise was gone! I asked him if he tightened anything or lubed anything and he didn't recall doing either. He suggested something may have shifted when the car was unloaded on the lift.

Well, over the past month or so, the noise has slowly returned. At first it was very faint but it is getting back to almost where it was before it disappeared. Does this point to any component specifically? What could shift when the car is on a lift and shift back slowly over time?