That's what most opponents of guns think will happen when guns become available to the law-abiding. It's yet to happen, though. Studies have shown that the more guns available to the law-abiding, the less crime there is in that area.
No need to stress, though - they have 6 months to draft such a ridiculously complex process to obtain a concealed carry permit that I'm betting there STILL won't be anyone legally carrying a firearm.
Illinois Concealed Carry Ban Ruled Unconstitutional By Federal Appellate Court
CHICAGO -- The long-standing ban on carrying concealed weapons in Illinois is over.
On Tuesday, a federal appeals court in Chicago tossed the state's ban on carrying concealed weapons, reports the Sun-Times. The court is giving the Illinois state legislature 180 days to craft a law legalizing concealed carry.
http://www.huffingtonpost.com/2012/12/11/illinois-concealed-carry-_n_2278114.html