Of course, you should only set limits if others aren’t doing it. If they’re not, then you should step in.
Remember, God is all knowing. He knows what choices people will make. You may not know what choices others can make. But, you can be very clear, on their level, what problems could result if they do something wrong. This isn’t just in the way of short term consequences (no TV, chores – not your own - sentences to write, or whatever), but also long term ones, like problems that could result if some bad thing gets worse.
In talking with them, you should emphasize that God, too, sets limits to help us.
