Recently during a race, I tried to switch the screen on my Edge 520 and it fell off the front mount - unfortunately into high grass. I spent 35 minutes searching it (drawing zones of lost Bluetooth connection, searching in the middle etc.). Finally found it.
I was able to get a connection from my Garmin Connect on a phone, but Garmin wasn't beeping even receiving SMS messages as I disabled sound on it.
I think there should be some kind of "forced beep", that could be invoked from Garmin Connect. It would make searching your device in a bush much easier ;-)