Yes they are and since all the argument is being dominated by the IN brigade and those on their side, they ought to be least in need of scaremongering. Maybe they don't have a very high opinion of us so they feel they need to predict doom in order that we don't give the wrong answer to the question...
Anyway, I may be wrong but I don't recall hearing anyone eminent on the OUT side of the equation indulging in this level of hyperbole.