My way of things may be differant from your normal routines. I prefer to get at their level, (literally), and explain to them the reasoning for "no!" You are the parent and, yes, you should take a stand. But remember they are only children. keep your head strieght and try not to lose yourself with them. if you talk to them like you would any other person then they will learn more than if you were screaming at them. hope you understand where im coming from!