As a wedding officiant and life celebrant, I discuss small details and logistics that can often disrupt a perfectly lovely ceremony.  My largest pet-peeve is cells phones and electronic devices that ring or vibrate (yes vibrations are heard!) during a ceremony.  I highly recommend to people that prior to the beginning of a service or ceremony, an announcement is made reminding people to turn off these devices. In my initial drafts of wedding ceremonies, baby blessings and memorial services, people can see how this is tastefully handled.  I do on occasion have people who are adamant about not wanting to make such an announcement, and so we do not. Inevitably, in these cases a device rings or vibrates at the most inopportune time, which was the case with wedding I officiated at this weekend, right before the vows, a cell phone rang, or should I say"played" a tune.   Previously we had discussed this announcement at length.  They assured me that no-one in their family would consider having a phone on. 

In the world we live in, cell phones and electronic devices have become second nature to us, like our arms or legs, we don't think about them.  It is never intentional that these are left on, but it is human nature, and while it disrupts the ceremony it also leaves the person who "forgot" embarrassed.  Ask your officiant or celebrant to make a tasteful announcement, and if you believe that your friends and family are different and don't need a reminder, you may wish to reconsider your logic.  Your insights are always welcome!