>>After their meals, smokers tend to chit chat while smoking,
>>loitering an extra half hour at the table while spending nothing.
You don't know much about the restaurant business.
The people who hang out after a meal (smokers or non) are a huge source of profit. They buy coffee and or drinks and or deserts, which are all very profitable. When they leave without buying any of those things, because they want a smoke, all that profit is lost.
I don't have too. I specialize in stock arbitrage, numbers and profit are my life. When a long time friend, who has managed a huge restaurant for years tells me the new law has mushroomed his profits overnight, I'm happy for him. Conversely, if belligerent smokers and wannabe restaurant owners complain about his additional success, I could care less.
P.S. After all, I don't fart in their face when they eat.