of the fact they were not travelling but what you are asking is a different aspect of the story
here s where the culpable responsibility of the parents begins
would they sedate their own child just so they wouldnt be bothered?.
secondly if they did discover the overdosage why did they not take her to hospital? did they panic and think she was dead when she might have been comatose? why lead this international campaign of deceit?? or did the campaign go out of hand?? were they overawed by the public response??
of course i am just theorising here so no need for any mccann supporters to go up in arms...
do it right - the first time!