the kurds are not voting for independence, so much as they are voting for a war of independence - one that they can't possibly win.
nobody is going to recognize the results of the referendum, either.....although, that doesn't mean anybody is going to step up enforcement measures.
the reality is that they've had de facto independence for years and that the outcome of the referendum isn't actually likely to change very much on the ground, besides perhaps escalate a civil war between capitalist and communist elements in the kurdish population.
they're going to need some kind of breakdown in iran, first.