My question is still the same. How many people would have had to have been complicit?
Answering instead of xtina once again.
Suppose, hypothetically, something very serious happened to a 3-year-old girl, let's call her 'Mary', late on the second day of a holiday. Suppose that in some way it was the fault, or responsibility, of her parents.
Suppose also that her parents came on holiday with three other couples and their infant children.
Suppose once more that no-one else on that holiday knew Mary before the holiday, with the exception of Mary's crèche nanny, who just happened to be Facebook Friends with the daughter of Mary's godfather.
All it would then need, to cover up her disappearance for say three or four days, would be the co-operation of the three other couples - and for the creche nanny to allow the parents to add Mary to the crèche records, and then, finally, to provide some confirmation by way of a statement verifying that Mary had really been there on those later days, when she actually wasn't.
No-one else would be needed.