I don't really know much about what kind of network chatter Android generates generally, but I imagine that, even if its encrypted, you can detect that there's suddenly network traffic to Google?
And then, depending on how silly the eavesdropping is, repeating the same message might cause the same encrypted payload to be transmitted?
traffic to Google is probably very common... and to be sure that you get the whole picture, you would probably need to intercept wireless signals going to the cellphone company which are also encrypted