Read other letters about this article
Thanks for your note; I've just posted this explanation at the end of the piece:
Readers have pointed out that it isn't safe to place a child seat in the front passenger seat -- a fast-deploying airbag can seriously injure your child. This is good advice for most cars. Fortunately the Smart detects whether there's an adult or a child sitting in the passenger seat. When the weight falls below a threshold, the airbag turns off (there's an indicator light which tells you it's off, too).