Hmmm, I've never really thought of putting the gear in neutral at a light but like others say.... It's a safety issue and that makes sense. And I do leave a little bit of distance between my car and the car ahead of me when stopped at a light in case I need to make a quick get-away from a carjacking situation or anything that would pose any danger to me and my passenger.

On-the-other-hand, I would sometimes, put it in park when waiting in a slow moving line at a drive-through like at Wendy's or Chick-fil-A, for other reasons.