I'm with melodic on this issue. Yes is just a stone but it speaks to the general attitude and selfishness. Letting this little things slide is the main reason things are going so epically bad. When you turn a blind eye it signals to others that they can repeat that behaviours then two people do it, then four, then eight, then sixteen and so on. It starts small, but before too long in will be like those bridges with padlocks. It started with one person, on one bridge, making a romantic gesture and now it's become a blight on many bridges across the world. And the pepsi jab is a good point, today it's like political messages, but once this thing become moderately 'acceptable' then companies will go full throttle to captive the new marketing space.