A recent study says 63% of smartphone users check their device at least once an hour. There's a hard core 9%  who check every five minutes. Ninety seven percent of smartphone users report checking their phone in the company of family and friends.  63% say they're upset if they forgetfully leave their phone at home.
About a third of respondents said they would be horrified if the information on their phones were put on public display. Fewer than half use pass codes. I JUST started yesterday. One in five surveyed 'fessed up to looking at someone else's phone without permission. If you want your private stuff to stay private, it's up to you to keep it that way.