I found this very interesting.DD1 who has just turned 2,has taken to smacking her baby sister to wake her up & I wasn't sure how to deal with it.It was too dangerous to ignore & smacking her would only teach her that its ok to hit people.
The first time it happened,I held her firmly,got down to her level & told her that it was a naughty thing to do,that we don't hit other people & that if she did it again,she would have to stand in the hall on her own until she calmed down.
She was very giggly & over excited,possibly due to having had visitors earlier & promptly ran over & hit her sister again.This time she went out into the hall,where she screamed & cried,when she came back in,she apologised to me,but wouldn't apologise to her sister.An hour or so later,she did it again,was put back into the hallway,where she screamed & threw things a the door.This time she said sorry to me & DD2 as soon as she was allowed back in.
After a very exciting day today,(grandparents had visited),she went to hit her sister again.I warned her what would happen if she did it & she stopped in her tracks & went off to play.I'm hoping that this 'time out' will continue to work,otherwise I don't know what else to try.