My husband used to urge me to say “No” more often to our children...just because. He felt they needed to get used to hearing it after all, life says no quite a bit, look at that Santa Barbara killer, couldn’t take no either. It is a modern phenomenon that parents are afraid of their children, even at three, maybe especially at three as three year olds can be horrid little bullies. We’ve been told for so long we have to “understand them” and “give them choices” (oh and they have to like all choices offered) and not spank them, etc. It’s no wonder we’re messed up.
I agree with your husband. Kids definitely need to hear the word no as often as possible. Yes should be uncommon enough that, when it is finally used, your kids’ faces should might up with joy.
Children will push the envelope until they get a no that is backed to the hilt with whatever will enforce it, including a smack on the bum.