I don't know what they teach you about safety in the ASE mechanics course, but I have two engineering degrees and have been involved with safety engineering, failure analysis, and accident investigation.

Letting the front control arms set on jackstands will not result in much spring compression or side motion of the control arms that might place a side load on the jackstands, but whatever the side load, it is only a small fraction of what would be required to overcome the friction force of the jackstand against a typical concrete surface.

The stands should be placed as far outboard on the control arms as possible and one should always verify that there is some spring compression from the rebound stops as the weight of the car settles on the jackstands.

When the spring must be removed, a jack can be used, but most service publications (all makes) recommend installing a safety chain between the chassis and control arm to limit spring rebound if the jack slips.

I continue to maintain that supporting the chassis while using a typical floor jack to support the control arm/spring to remove the strut is considerably less safe (if not foolhardy) than supporting the car on jackstands under the control arms using the car's weight to keep the springs compressed.

Duke