A bride checking her phone during her wedding?! Are you serious?!  The girl's father had just walked her down the aisle when she pulled her phone out of her bra to check it. This has got to be an unparalleled low in digital etiquette!...Or lack thereof!
We've all been offended by someone who seemed to be paying more attention to the little electronic candy bar than the person in their immediate company. I once had a dinner date with a woman who pulled her smartphone from her purse & put it on the table before she even sat down. I didn't ask her out again.
It seems like some actions would be obvious breaches of etiquette, while others clearly present a danger, like texting while driving.