It is proper Netiquette to view content suitable for a public audience in public. Don't look at anything everyone can't see.
Smartphones screens can be seen in public. They cannot be seen by everyone and most people do not look at other people’s screen. These facts mean that anyone can see anyone else’s smartphone screen if they watch them long enough.
If you do things on your smartphone that are not public activities do not do them in public because anyone can see your screen if they watch you long enough.
Consume acceptable content in public because we should not be subject to offensive media.
Published on May 16, 2015 | 0:38 Seconds | Science and Technology
An introduction to Smartphone Netiquette. Keywords, graphics, and symbols.
Published on February 14, 2012 | 1:12 Minutes | Science and Technology
The Rules of Smartphone Netiquette by David Chiles from a planet in the Cell Phone Cybershphere.