I agree with you most whole heartedly. If a parent will not follow through with the threat, then there is no accountability for the action. I only make threats that I will follow through with in the event my kids stray from the path.
I pray (by God's most glorious mercy) that I will not raise my kids to be the perennial victims that liberal society glorifies.
It goes without saying that you always praise good behavior and a job well done, but I think never lying to your kids teaches them the most.