The Departments of fish and game put "antlerless" seasons for a reason. If you have an antlerless tag, shoot an antlerless deer and get over it. There is no harm in killing a "button buck." If you are concerned about hitting one, don't shoot any that don't have antlers. Now, it is pretty easy to tell the difference, though it is not guarenteed. If a larger antlerless deer has one or two smaller ones with it, don't shoot any of those guys. I would rather tag a fawn, than shoot the mama and leave the fawns to fend for themselves for the rest of winter. Find a deer that seems to be more by itself, shoot it, and move on.