I am against using hen calls before the season. If more hunters witnest what I have they would stop the practice. In my early years hunting turkeys I read you should never hen call to toms before the season so I didn't. One morning I was calling to a couple goblers.
A vehicle stoped at a pull out and cut the engine. The gobling stoped before the truck came to a rest. The unmistakeable sound of a box call sung out a few times, then a few more. After waiting a few minutes the vehicle started and drove off. One minute later the gobling resumed. Now this happened two more times with diferent vehicles and calls that morning . Yup, its pretty simple.