I took that fihing line idea one step further a couple years back by takeing a Knight and Hale tom coffin push-pull call and makeing a bracket for it so I could stake it under the decoy. Ran the fishing line back to my set up and gave it a tug now and then. It worked! I also use that call set up when I'm not useing decoys to sound like a moving hen or multiple hens in two seperate areas. I'll place the call set up a few yards behind me. That way if a tom seems like he wants to hang up I can make him think the hen has lost interest for him not commiting and is starting to move away from him. Had that work for me twice.
If it gobbles,runs on gas, or is married to you it will give you trouble!