Thought I'd jump back into this - I don't smoke, I quit when I was seven - I got caught! But I digress.
It is my experience that Europeans, including folks from the UK smoke much heavier than North Americans. The non-smoker in Europe is in the minority. This is an observation for those who have entered this discussion using the North American point of view, just to aid in the understanding of those Europeans who have advocated inflight smoking - the anti-smoking stigma just isn't there as it is on this side of the pond.
I am against smoking on board primarily for safety reasons. Second hand smoke is, pardon the pun, a secondary concern only.
Fire on board an aircraft is The Most Serious Emergency that can occur. All it takes is a shot of turbulence while that butt is smoldering away while you're lost in concentration in your magazine/laptop/pretty girl sitting next to you. Once the butt is on the floor or in the seat cushion area, it may be either forgotten or inaccessible. Inflight seat fires will spread like wildfire. And it's not the fire or immediate smoke that will be dangerous - it's the toxins released by the burning/smoldering plastics - they can kill very quickly.
Given the circumstance of the Learjet crash yesterday, when things go wrong on an aircraft, they can go wrong fantastically fast and in the most unpredictable manner. If an airline has the opportunity to reduce a particular risk by banning open flames and smoldering ashes, why not reduce the risks?
As I mentionned in another post, a great many of contributors to this great forum are neither pilots nor flight attendants, so don't have the same insight to air safety that is ingrained in both groups. This is not a criticism, but simply a statement to heighten awareness. Flying is regarded by most non-aviation involved people as dangerous. Personally, I think walking a beam on a highrise construction project is dangerous. But in both cases, those who are closest to the action, so to speak, are best able to ascertain the risks/dangers.
Most passengers opinions of the pilots and flight attendants perceive them as necessary to pay 99% of their attention to passengers as customers and 1% to safety related matters and getting to destination on time, when in reality its the other way around.
It's been a good discussion and in closing I would wish that everyone who flies as a passenger in an aircraft realize that there is usually a very good reason for everything demanded of them.