Alignment - a simple question

[car-nut]

Several threads in here state that one should move the car, either back-and-forth, or better yet, drive it around the block, when changing camber, toe-in etc.

A SIMPLE QUESTION: I just took my car to a reputable wheel alignment shop. They did their laser job, without moving the car whatsoever. I also checked the YouTube, and the same was done on a Mercedes (i.e., without any movement.)

Your en-lighting views are appreciated in advance.
Cheers,
Zack

[Jesse16]

I'm an alignment rookie but did a decent one with some help from a friend using strings. I believe and others will chime that because we made our adjustments with the car jacked off the ground, wheels removed. Re-assemble, lower. Moving the car or a drive (ideally) gives the rubber mounted bits a chance to re-settle to their natural loaded condition before measuring. If you're aligning yourself, you're likely the picky type.
One exception, minor toe adjustment to the front to align the steering is relatively easy to do and I didn't do any car moving.

[eastbay]

Alignment racks have turn tables and slip plates so the rack moves with the adjustments and does not load up (or bind up) the suspension. Most threads on here are about aligning on the floor which can, if you are not careful, load up the suspension. The driving around or rolling practice is to unload the suspension after your adjustments.

[aston@ultrasw.c]

you can make your own slip plates by squirting WD40 into 1 gal freezer bags and placing them under the tires

[ganun]

Freezer bag beats spraying silicone on the epoxy garage floor!

[car-nut]

Now it makes sense; thanks very much!
Zack

[Chuck.H]

I made slip plates from two vinyl tiles with grease between them.

That said, even though they are very slippery, I still roll the car back and forth. I can see the suspension settle as the fenderwell gaps decrease when I do this.

Chuck.H
'89 TurboLookTarga, 384k miles