A level of confidentiality

One of the things I like about having Mood Sentry on my phone is the level of confidentiality it provides when I'm working my program in a public place.  I often go to a Starbuck's at lunch, and sometimes pull out my phone to review my entries and/or update my entries.  It's a good time for me to take a break and reflect since the morning is over and the afternoon is about to begin.  The other people in the store really have no idea what I'm up to.  I've pulled out self help books in public places like this, but prefer not to.  This is why I have the references in the app.  I can refer to them when making entries, or even just review them on their own.  I wonder if the other people staring at their phones are doing something similar?  Not with my app, I don't have enough downloads to justify that thought!