Dave, you seem to think this is all of us are cooking up a conspiracy theory, we aren't, It's just what happens
I agree its not normal behaviour but as Mike points out, they can't ever be described as a normal family
The Queen herself I presume, they didn't make the plans behind her back, as Brumerican says they've been in place for decades and she was integral to the Planning. The overall plan was Operation London Bridge with Operation Unicorn for if she died in Scotland. There's also Operation Spring Tide for Charles Ascension to the throne