Although the idea of incident detection is great i do feel that the implementation leaves a lot to be desired.
Assuming the Edge 830 actually connects to your phone reliably here are my experiences so far.
So far it has triggered on a few occasions when I stop a little abruptly at my destination and shutdown the unit, causing me to rummage through my ruck sack to intercept on the phone rather than the unit itself.
Today it excelled itself, whilst cycling along my phone started making noises to indicate I had crashed but the Garmin did not and thus I had no prompt on the unit to cancel the alert. Given that the phone was buried in my rucksack I decided to ignore it. Shortly afterwards the Garmin said my wife was trying to call me, as I was only a couple of minutes from home I just cleared the call from the Garmin. I got home just in time to catch her in a state of panic leaving the house to go to the scene of the alleged incident.
Nice idea Garmin but your implementation sucks :(