What do you do with your phone if you do bring it into the meeting? I agree that they can be distracting, but I don't think you need to leave them. The trick is just to get in a habit of turning off the sound on your phone. I also don't think smartphones should be on the table in from of you. It seems so common that even on a date or a business meeting people have their phones in front on them. Not that we have always-on screens, people can often get distracted. This can make the other person feel like you're more interested in the phone that him/her.