The Royal Family love to keep things secret. If its immoral or illegal you can pretty much bet your life someone in the Royal Family has not only done it, but they've managed to avoid criminal charges, have had their MI5 stooges hush up the mess and their friends in the judiciary slap ridiculous lawsuits on the free press to keep the information from the public.
The Royal Family and their supporters often say that the only income the Queen gets is from the civil list. However, this is not true.
Members of Parliament must declare their interests for the public record. But the Queen's finances other than the 'expenses' of the civil list are strictly out of bounds, as is the exact detail of who owns much of the property that the Queen treats as her own. The Queen negotiates how much tax she feels like paying (which is significantly LESS than she would pay if she was subject to the same law as everyone else).
Tonight the BBC attempts to get some answers, although it appears it will take more than good journalism to find out exactly how much the Windsors have been hiding from us.
BBC News - My quest: How rich are the Royals?