After my wife and I exited our TCH and closed both doors, I tapped the driver side door handle button as I usually do but instead of locking, a continuous alarm tone sounded.

I opened the door and checked the dash to be sure I'd turned everything off properly and closed the door again. Pushing the button caused the same tone to sound. I pulled my fob from my pocket and pushed the "lock" button -- the car locked immediately.

Upon returning to the car later we realized the TCH had simply been warning us that it knew my wife's fob was in her purse on the floorboard. The alarm tone means "You can lock fob #2 inside if you want to, but the TCH is not responsible if you lose fob #1"

 

If the second fob is in the car, doesn't that mean that anybody that walks up to the car can open the door and drive away?

 

If you leave the spouse fob in the car and touch the door lock it will not lock as it assumes you left your key in the car. However if you want to leave the key in the car, say the wife does not want to take her purse with her, you can lock the doors with the lock button on your fob and the car recognizes that you must indeed have it and it locks the door. However it is smart enough to kinow then that it needs to be unlocked by either someone touching the fob unlock button and it deactivates the ability of the other fob to open the door.

So yes if you want you can go ahead and lock the extra key up but you'll have to use the fob button to lock the car.