I don't know if this was already discussed here :
Why MJ shows off his children to the world 2 weeks before he died ??
Think he planed to do it a long time ago ... listen from 4:10 in the famous interview with Giraldo , he clearly revealed his attention to let them go on the stage with him.
[youtube:5ic9bb95]http://www.youtube.com/watch?v=7dI46XY8S9E[/youtube:5ic9bb95]