AFAIK, people are rarely caught simply for texting and driving. to actually catch someone in the act, a cop has to drive by at the right moment and see the driver texting. more often, sms records will be examined in a crash postmortem. if texts were sent right before the time of the crash, it's good evidence that the driver was illegally texting. I guess if the police really care, they can do the same thing after pulling you over for erratic driving.

eating food doesn't leave the same digital trail. if a person crashes or gets pulled over for driving erratically and there's half a sandwich in the passenger seat, there's no way to know whether they were eating while driving or whether they just ate half of it in a parking lot 30 minutes ago.