I would lose all my faith in human nature if the parents are found to have had any hand in her disappearance.
But let us take the worst case scenario and imagine the unimaginable.
Suppose the parents,both doctors,hoping for a quiet night out,had dosed their children with a mild sedative but had given a lively and restless little girl a little bit extra to keep her asleep.Visualise their shock and horror upon their return to find her having fallen badly thanks to being dazed by the extra sedative.Their beloved daughter dead thanks to their ministrations.What thoughts must have gone through their minds!What would people think of them?Who would trust them as doctors again?What shame and shock would course through their bodies and souls?Who knows what we might do in similar circumstances?Would we enter upon a path of denial?Our minds play savage tricks on us.And so the sequence of what follows would be both extremely regrettable and sadly completely understandable in their desire to ensure that the twins did not lose their parents and so the charade would have to be played out.They would be more to be pitied than condemned.
One little fact bothers me.Why would anyone abducting a child place its comfort toy on a high shelf rather than let the child take it with her?Would any abductor not have let the toy fall to the floor,if it fell fom the child's grasp?
God forbid that any of what is put forward as the worst case scenario carries any credibility.

It's been so long now since she went missing that you tend to think it's not looking good. Bless her wherever she may be.

I just don't understand how they could have staged the big 'disappearance' and why? Surely if it was a tragic accident you shouldn't put yourselves through all that...the whole thing is so so strange and bizarre. If they are innocent they must be going through hell and are they ever going to find out what happened to Madeleine? If they aren't...well it doesn't bear thinking about.