Imagine someone telling you - plastic cups are forbidden in companies. Yep. Coffee machine works only if you put your mug in. Crazy isn't it? It happened in France. Guess what. After a couple of wtf days, nobody really cares and get the habit to use mugs. Imagine if a law has just "encouraged" this change. People would have thought it was far too hard. Only law can change people's habits. I don't believe people - of course except a small percentage - can put constraints on them for civilization's survival. You?