The one strange moment came when I discovered a surprise "feature" on my iPhone.
Although I mainly played guitar arrangements and attempted to channel Frank Sinatra, I used backing tracks on a handful of instrumentals to rest my hand. I record all my backing tracks myself. It's an investment of time and effort, but it's fun, and the finished product is a backing track specifically tailored for my needs. And because I have all the files, I have complete freedom to tweak these tracks in the future.
Once I'm finished creating a backing track, I load it on my iPhone, which becomes my "band in a pocket." I just hook the iPhone up to my amp, and I'm ready to go.
When I play a gig, I always make sure to set my iPhone to vibrate only. It's annoying to have someone else's phone start ringing when you're performing. It's REALLY annoying when it's your own phone, and I have a particularly obnoxious ringtone. I've included a short YouTube clip for your enjoyment.
Fortunately, this teachable moment occurred in a roomful of friends. Lesson learned. If the iPhone is plugged into the amp, it's airport mode from now on.