As it stands, the Madrid government is almost provoking the catalanista electorate into turning out and voting Yes-Yes. Or, should I say, "si no, No!" 
Exactly, that's the situation right now. The options in play are independence or statu quo, with an ambiguous and not defined "statehood without independence" option inbetween (the "Yes-No"). There is an overwhelming majority of Catalans disaffected with the statu quo, so inflexibility and "do nothing" policies provoke them to choose the "Yes-Yes" option.
The conflict here is between the will of the people to vote on their future and the rule of law. While it's illegal to act against the Constitution in order to secede unilaterally, when the letter of the law is contrary to the will of the people, it's legitimacy becomes questionable.
The only example that I know dealing with this complex question is the Clarity Act passed by the Parliament of Canada. While contexts are different, I think some of the key points are applicable.
http://laws-lois.justice.gc.ca/eng/acts/C-31.8/FullText.html
What does this mean? Seems very strange to have it as an option if people won't know what they're actually voting for.
