Is it Ok for your Children to Challenge your right to exert authority over them?

I think that is is ok for my children to challenge my authority within reason. Obviously if they want to walk off a cliff and I say no, I expect to be listened to because i know that walking off a cliff is a bad idea while they may think they can do it and live. Saying that, children need to constantly test the boundaries, to see what they can and cannot get away with. It gives them a sense of stability, a way of knowing that there is a line and that while they can push away at it, I will not let them cross it. It's how children learn to deal with authority, I know I did the same thing when I was a kid and im sure many others did too. I think it actually prepares us to deal with the chain of authority when we are older too. Once we have learned as kids how much we can push, we take that knowledge with us as we grow older and go into the workplace. It's not a big deal in most cases although, there are some children who just cannot understand or accept authority and those children are the hardest to bring up because they have no innate sense of right and wrong, what you can and cannot do. In fact i think those parents with children who just keep pushing are heroes. They take all kinds of rubbish from their kids and still plough ahead trying to teach them so yay for them!