Remember when the chimp is hitting Jesse? He thinks it's Becky being frisky, but he says "was Uncle Jesse a bad boy?" Now, i won't get into what the purpose of that would be, but I will say that if it was just Becky playing around being frisky herself, he would have said "was Jesse a bad boy." He wouldn't refer to himself as Uncle Jesse with her. He would only refer to himsef that way to one of the girls. Of the ones who played "house" with him when Becky was there, Becky would have only seen Michelle. With me so far?
So, if Jesse thinks it's Becky, and he says "Was Uncle Jesse a bad boy," he must figure she's imitating Michelle. But, let's say she would do that imitating Michelle (like he thinks). That means he knows that Michelle must know the concept of hitting for being a bad girl/boy. A child would not pick that up from a friend this early. True, she plays house with Teddy, but usually it's with dolls they punish, or with adults with the adult as the child. Not only that, but Michelle wouldnt' copy it just because a friend does it, if nobody mentioned it with her, she'd just think it real weird.
We know Danny and the others could never hit. I believe that D.J. did what happens often psychologically here. D.J. reacted, though she wasn't proactive, in teaching Michelle right from wrong. And, if Michelle did know this concept, that means D.J. had to at least mention it as possible.
I don't think she would hurt her, and while she might give light fwaps as a last resort (it would be a spanking to Michelle), I don't think she ever spanked Michelle. However, I think Michelle knew it could hapen. The most likely time is before the wedding. D.J. may well have told her just what would happen if she dove into that wedding cake like Michelle had with the samples. I do think it's possible D.J. gave a few "love pats"/light slaps, but I doubt it. They would talk about it, and Michelle would be scared by just the thought, since it would be so unusual in their house.
So, any big phase of defiance because of a sugar rush or just general attitude, if Danny's ignoring it, D.J. would try everything else, and if nothing else was working,s he would sit down and have a heart to heart talk about spanking, and that would be all that was needed. Of course, maybe some of you think she did do it with those light fwaps a few times.
But wait, you ask, would Danny approve? Well, he might if told she wouldn't hurt mroe than her feelings, but also, we don't know what Pam and he discussed regarding having a Jesse-type kid. We know Danny never hit ("Silence Is Not Golden"), and the others couldn't, either. (Jesse - same episode - and Joey - who would never hurt a fly.) If Pam and he decided that if nothing else worked, they'd talk and he'd just let her do it, it's possible.
Or, Michelle could have just picked it up when someone's reading one of Joey's old comic strip collections and it's mentioned. (Dennis the Menace half a dozen times, for instance, though he's almost always in the corner.) But, that then brings to question, why would Michelle copy it, with Becky then possibly copying Michelle playing house?