Its worse than that. Depending on your broker, if they can't find shares to borrow, they will NOT allow you to exercise your options to establish a short position. Even if they are able to find shares, they will charge you a high interest to maintain the borrow.
Varies drastically from broker to broker on how they handle this. Some are simply much more 'legit' when observing the naked-shorting rules.
Using 'lower quality' brokers like Etrade, ThinkOrSwim, TdAmeritrade will actually benefit you in this instance since they should just allow you to exercise even without borrow shares.