A receptionist in Oklahoma was asked by the hiring manager to keep an eye on the job candidates in the waiting room and report back to him which ones talked on their cell phones, checked messages or texted. Those candidates were not hired.
My husband has stopped wearing a watch and uses his phone as a time piece. People make notes or save questions on their Blackberry and would use that as a review prior to the interview. Might we all be safer if we instead opted to take in a portfolio with questions and notes listed and wear a watch? Just leave the phone in the car! Your goal is to leave the impression that you are focused on the business at hand and not distracted by other things in your life.