Yup. And, logically, some of that detritus will be tipped back down the bore next time the barrel and mod are mated.And the moderator will collect any crap dragged out by the boresnake, surely? Which probably won't do it (the mod) any good.
Many carry rifles on shoulder slings with muzzle up during stalks. That is plenty of time and agitation for the crud so deposited in the mod to be encouraged back into the bore. If you choose to walk with a round chambered, the carbon slough falling into the barrel is likely to build a mini sand castle between bullet and throat. I cannot see a better way to accelerate throat erosion.