Motorola recently polled 1000 prosumers regarding their mobile attitudes and use. Their results were published in this nice little graphic:
One of the surprising results is down in the lower right-hand corner of the graphic: "Nearly half of people log into unsecure wireless networks." This in addition to the 25% who store banking information on their wireless phones. It's amazing to me that at the end of 2011, we're still having this conversation: AVOID UNSECURE NETWORKS LIKE THE PLAGUE.
I think any breach or loss of one's electronic information would violate Rule 1.15. I couldn't imaging explaining to the state's bar association (or your malpractice carrier) the reason your client's information was lost.
One big question is what would you do with your phone if you lost it? What about the data that's stored? I suggest one of the many "wipe" or backup programs available in the Android Market. One of my favorites is Where's My Droid? by alienmanfc6. There's a free or pro version ($3.99) available.