You may feel like you are losing a limb by giving up your phone on your wedding day. What if there's a problem? You need pictures of the day! Relax - it's your wedding day - you shouldn't be focused on anything other than saying "I Do" and celebrating.
First of all, to keep your mind at ease about problems, appoint a day-of Contact Person. This person should be with you the whole day, and be in tune with the wedding plans. This is the person who will handle issues with who needs to be where and when, and emergencies, etc. (Make sure your Wedding Professionals know who this person is!)
Next, to keep you from distractions, designate a specific trusted person such as one of your bridesmaids to take your phone for the day. Give her your password and let her handle the phone calls and take candid pictures and videos. You'll be surprised at what this different perspective can do, and what memories can be captured.
Bottom Line: Your wedding day will pass by in a blur. Do you really want to be tempted to check your phone every few minutes? You want to remember every moment you can about the day, and getting sucked into your phone all day will take away from that, so give it up.