I was curious about the standard immobilizer on my 2015 R3T so I tried out the saddlebag key in the ignition. Aside from being difficult to turn with very little sticking out of the ignition, it started the bike without a problem. I double-checked the VIN a few months ago as despite my title saying it's a 2015, a dealer told me based upon the VIN it's a '14. Triumphs VIN decoder (actually i think it was their recall search) confirms it is a 2015.
I can confirm on my 2015 R3T the luggage key did start and run the bike for about 30 seconds.