I personally love that it has the ability to lock when you walk away. I never have to take my key out of my purse.
I do know what you mean by the alarm going off when my husband was in the car still. However, I usually just leave the key with him before I get out of the car and then it doesn't lock in the first place. This happens rarely for us.
I have left my purse with the key in it overnight, and did not lock. So not sure why that would happen. Maybe I just got lucky that one night
Have you tried that again, where the car locked with the key inside it? Just to make sure it wasn't a one time thing?
This is a different issue, but my lights would stay on in my garage if I didn't lock my car. So it also helps with that.
Only negative I can say, is that I go out to my car in the garage and forget to unlock it first.