Very short update: I added the following support notice to the FAQ page. The issue will be fixed at the source but there are already meters in the distribution pipeline that are affected, so this will probably affect new customers for a while yet.
Support Notice April 28 2016:
Some new customers are reporting that the Mooshimeter does not respond to the wake-up procedure outlined on the instruction card. A batch of Mooshimeters was released that was never placed in shipping mode. They are already awake and therefore will not respond to the wake-up procedure. You can connect directly to these meters by downloading the app.
Sorry if this caused confusion!