Magic Referendum Fairy
The big wave of the wand would be when Shetland decides that it wants to be independent itself or stay in the UK.
Why? The way that the first use of the word 'Shetland' in "Scotland's Future: Your Guide to an Independent Scotland" is on p290 is utterly typical, as is the second on p301, where it claims what is - by the SNP's favourite way to decide this - undeniably Shetland's oil belongs to Edinburgh.
Shetland could go independent and thrive without mainland Scotland, but mainland Scotland could not go independent and survive without Shetland.