Law enforcement officials trying to rein in violent smartphone theft have criticized cellular operators who they say rejected a solution that would help address the problem."It is highly disturbing that these corporations rejected a proposal that would have helped keep millions of consumers safe," San Francisco District Attorney George Gascón and New York Attorney General Eric T. Schneiderman said in a joint statement Wednesday.The officials have been pushing for a "kill switch" that could render smartphones inoperable after they're stolen, reducing the incentive for crime. But news reports this week suggested carriers have rejected the idea."If they did so to protect their own profit margins, as several recent reports suggest, it is even mo