[xDrive50i]

I have to see if I can find the time to do a video for you.

Last time I tried the spare key to unlock and start the car, my remote was approximately 15 to 20 feet away. The car was parked just outside my front entrance and the remote was in my house inside my jacket that I had left by the front entrance.

I just checked the 2009 owners manual and it does seem to only mention the remotes for the emergency start procedure and not the spare key.
I know that the car did start when I used the spare key, and I am pretty sure the car was NOT communicating with the remote keys as they have to be fairly close or even inside the car for the communication to work!

Just out of curiosity, why do you want/need the spare key???

The remotes have a mechanical key to unlock the car in case the remote doesn't work and then you can just use the remote to hold it up to the steering column to start the car so you don't really need a spare key...

I personally never had a need for the spare key.