Thanks for the quick replies.
I have SF and NATO and like having the option for my infantry to pop smoke, especially before they run across a street....but I recall a thread where this was discussed on the CMx1 engine where gamers wanted infantry to throw smoke but BFC rational for not letting them so was that is was not historically correct. So I was surprised to see this in the manual.
P.S. I searched the archives but could not find the thread I'm thinking of.....maybe I was drunk when I read it and I'm not remembering correctly.