Sounds as if this law as been coming into effect since 2006, and has had legal challenges against it at some point by tobacco firms. The latest I can find on the subject is the followng

http://www.globalsmokefree.com/gsp/index.php?section=artigo&id=120

http://www.news.com.au/dailytelegraph/story/0,22049,24007980-5001028,00.html

We visited Kenya this summer and stayed at the Voyager where the smoking ban was definately in place. We didn't travel out of the hotel much apart from safari and a half day trip to Mombassa where I can't recall(as a non-smoker) whether there were restrictions regarding smoking although I am sure there were restrictions in Mombassa airport.

Mandy