I have polished at least a few hundred sets with asphalt. You should try it, its really FUN!
I've been known to pick a few rock's out of my snow's. Only really big rock's would I pick out of the cars tires, or rock's that make noise or knock my wheel out of balance!
The truck's, just drive fast and they will come out, trust me.
My last 3 4wd's I would stop and pick out the bigger rocks stuck in the tread, when I got back to pavement. If I didn't, as soon as I reached higher speeds the rocks would come out, and hit the rockers/lower doors, and take chunks out of the paint.
OCD? maybe, but at least the paint wasn't destroyed by my own inaction.
I should also add I would be airing the tires back up at the same time. Plenty of time to check out the vehicle for any issues incurred while off-roading, and pick out the big rocks which would be come projectiles for my bodywork, or anyone following behind.
Doing it now on nearly new tires to clean the back side and inner rims. Somebody must have driven on a gravel road or construction site as I'm picking out a whole bunch of them. Also a few nail ends that if left there, would have penetrated through.
Never done that but I do pick out the seeds on my bananas.
Nissan actually a technical service bulletin on this for the z-sports car.. I think it was the 370z. They talked about removing all the stones from the tread before balancing the tire, that mass could affect the balance. I thought I'd try that on my scion tc, and I actually got about 3oz of weight from the stones in the tread! That definitely could affect the balance. So nope it's not nuts when you're balancing a tire or if you suspect the balance is off, check for lots of stones.