My hometown SP has me use CoverMe, an app for Android and iOS. It's not a huge city, she is known around town with her regular day job, and she keeps a small clientele base...so she puts extra effort into maintaining her privacy.
With CoverMe you can basically send texts with options to auto-delete after they have been read. There are other functions (data vault, private calling, ...) and I'm sure there are plenty of alternative apps available.
Do other SP's use this, or is that just too much hassle and paranoia in a city big enough to provide a little anonymity already?