One area I hunt has an old doe that throws off twin button bucks each year, she' s huge and I have seen her for the past 4 seasons. Everyone that hunts the area knows her and we have all agreed to let her walk.
If a doe comes within range with only a single young' n in tow, I' ll harvest her if given the prime shot. But only if the fawn is out of spots.
Your last question:
Should we not be shooting them at all?
Depends more on your buck / doe ratio IMHO. The area I refered to has a ratio of 1 to 6 - 1 to 7. Many mature does are harvested each year and the ratio has remained constant over the last eight seasons. Even with a slight increase in the buck population the last three years, the # of does have increased proportionately.