DDOS attackers are charged under the Computer Fraud and Abuse Act. They charged one of the kids from the Anonymous DDOS on Scientology with "unauthorized impairment of a protected computer in violation of 18 U.S.C. § 1030 (a) (5) (A) (i), (B) (i)." http://secretdox.wordpress.com/2008/10/18/usa-v-guzner-plea-...

I realize this is the same statute that they are going to come after this guy but they couldn't get him for impairment of a protected computer. They would have to try charging him for unauthorized access, but my point is that Apple is implicitly authorizing everyone in their stores to access their computers.