[JumpCrisscross]

> Perhaps by holding a referendum to get their views on the matter?

Playing devil’s advocate. Referenda may prematurely compress a multidimensional discussion space into binary options. There’s no “I’d prefer to stay in Spain if X, Y and Z.”

[Osmium]

True, I was being slightly facetious. That's why the wording of the question is so very important, e.g. in the case of Scotland there was no "third option", which would have been further devolution of powers.