Wow. Two on the exact same weekend. That's nuts! Could this be the result of moon phases or solar flares? lol j/k
Obviously there is "something" to this dead battery issue. Whether it's bluetooth or some other combination of factors it's important that the incident at least be reported to your Volt Advisor, or better yet have a dealer check it out and get a "case" active with Volt techncial assistance.
There just hasnt been enough of these occurances in the wild to get much going on it.