Good idea. I am going to order one online and keep it in the glovebox.
I am also seeing an increase in odd occurrences with my anti-theft system. Sometimes the remote (brand new from dealer) works, sometimes it doesn't. When it doesn't and I use my key, none of the lights that usually blink when you arm or disarm the alarm blink. But then, without rhyme or reason, the remote will work the next time.
I read about a spider box problem and that this may be a cause. Have you dealt with this yet?