Has anyone ever used a Swiffer duster from the grocery store? It doesn't have those coarse waxy threads on it like the california car duster has. Swiffer seems really soft and picks up dust well. I've used them and it seems like its knocking the dust off when you flick the duster with zero pressure.
Yes, I've been using them for some time now. I was skeptical at first but not any more. On a new car, which is now 16 months old, I have used them about 3x per week (essentially after every 1 or 2 drives) over that period and still do not have enough swirls or fine scratches to justify compounding.
I don't think any of those are due to the Swiffer, since I always sweep lengthwise and the few fine scratches I have are fine and random directions. If the Swiffer were scratching, the repeated use in the same lengthwise pattern over the past 16 months would be visible. It's not.
Lately I've been blowing the car off first (you could use compressed air, leaf blower, or whatever you have handy), which removes a good bit of the dust, but also will blow off any bigger grit. I'm not sure this step is absolutely necessary, since the Swiffer is such a light touch, but it surely can't hurt.
Normally, one Swiffer duster does the whole car and is barely dirty. The dirty areas are generally the same: lower panels behind the wheels, and back of the car. I do those last, and then I do the windows. I don't reuse them after 1 use (but keep them around for brake dust cleanup, before throwing them out)
A few caveats: You want a good layer of sealant, which seems to keep the dust free to sweep off. Maybe 10% of the time I toss the Swiffer midway and use another one, if the first one gets fairly dirty (judgment call).
If your car is not garaged, and/or is exposed to dew or moisture, use a waterless wash or do a full wash instead (since the dust is then bonded and cannot be easily dusted off).
If the car is dirty enough, I'm sure even the light tough of the swiffer could drag some grit across the paint and scratch. So you still have to use judgment, and best to use a waterless or a full wash if you have any doubt that it might be too dirty.
I have no less than 3 Cali-Dusters. Depending on the vehicle one or the other gets used, not just during pollen season. 
I keep a bird poo/dusting kit in my trunk (well actually in ALL my cars) and my wife will tell ya', I might just do a QD on the car after we go out to eat, BEFORE we can even drive home!