I just want to be clear that I don't have any problem with anyone trimming, deburring, sizing, etc. to their heart's content; I'm merely trying to debunk some misconceptions.
I inspect all brass I load and, in my experience, an average of no more than 2 or 3 cases per hundred that I receive new and shipped from places like MidwayUSA, Huntington Die Specialties and Nosler are unsuitable for reloading right out of the box. Brands have included Nosler, Norma, Winchester, Weatherby, Remington, Starline, Quality Cartridge and probably some I don't remember. Much of the brass has come in plastic bags and sometimes has come loose in the box during mailing and has rolled around a bit. If the mouths are WAY out of round, if the body has been crunched or the primer pockets are off center the cases are either processed or discarded depending on how bad the defect is.
What you may have to do to new cases also depends on what gun you're shooting them in or what bullets you're using. For instance:
1. Boat tailed bullets are very forgiving regarding mouths out of round and if you seat them in an out of round case mouth, everything will straighten out and all will be well.
2. If a bullet is perfectly flat on the bottom or is a cast bullet, I will chamfer the case mouth.
3. If the case mouths are so tight that shaving of the bullet occurs, I'll chamfer the case mouth. This will hardly ever happen with boat tailed bullets.
4. I have to size new brass to be shot in a 460 S&W Magnum revolver or the bullets will come out of the case under recoil even with a good crimp. In loading for that gun, I not only resize the new cases but also have a Lee Factory Crimp Die I use to secure the bullets (i.e., my loads are not downloaded at all). In loading for my 460 S&W Magnum Encore handgun, I don't do anything to new brass since its a single shot.