No Smoking?

Are the signs for real or not? If anyone of you went to McDonald's at Projet petrol station which is located at Kuchai Lama, KL, you'll find this interesting. Around the McDonald's open area, there are "NO SMOKING" signs. But as you look around, you'll find people smoking at that particular area itself. The crews working there doesn't seem to give a jack at them at all. As you walk further away but still in the petrol station, something even more interesting that will attract your attention. There is a sign there that says something like "No smoking here, it is dangerous as it can cause explosions". Will it actually happen when people sitting at McDonald's smoke? Or the signs are just designated to decorate the place up?