In the course of an awesome oceanfront ride on Saturday, I suddenly heard a weird, alarming noise. It sounded a bit like tuning an old radio; I stopped and started up again, and it came back. Fortunately, I didn't hear it again (relieved, as I was in a remote area by myself), and rode back to my car planning to post on the forum about it right away.
It wasn't until I packed up the car and took my phone out that I realized... it was the new OWheelBuddy app notifying me of 50% battery! I LOVE this app! Thanks for all your good work, @SeeTheInvisible!