I completely agree that any pressure while the car is dusty/dirty will cause scratches. But my responses are based on the OP's situation and question.
Originally Posted by Templar
Anything that touches the car and rubs against it (no matter how light it is) will cause some sort of friction and some light marring. I don't care if it's a california duster or a microfiber towel.
Any DRY item rubbing it will cause more marring than something lubricated with a shampoo and water (which also slightly lifts the dirt and dust off of the surface of the paint). This is just science.
I have a california duster and I do use it, and yes it causes some light marring that is barely noticeable, but it DOES do it. No matter how "lightly" you dust the car, it causes a few small marks. Saying it doesn't at all if you know how to use it is slightly misguided.
There is no magic item out there that will not mark up the car when you rub it against the paint when the car is dry and you're not washing it. Even when you wash it by hand, you're going to put some swirls in the paint (depending on your experience it might be a lot less than others). In order to truly remove the swirls and small scratches, the car needs the proper detail done and must be clayed, polished, and then sealed/waxed.
Anything done to the top level of the car after that has a chance to add swirls and marks.
@ OP, if you don't mind some minor swirls that you probably won't see (unless you look up close in direct sunlight), then just use a QD spray and microfiber towel or a California duster. Don't apply a ton of pressure, just enough to get rid of the dust. I recommend the full treatment though. Use the two bucket wash method with two different wash mitts, grit guards at the bottoms of the buckets, etc... You'll get a very good wash and you'll have very little marring of the paint. Then you can procede to clay/polish/wax.