There's not a helluva lot to smile about when you're sitting in Fort Lauderdale's molasses-slow traffic during winter. The tourists and snowbirds swarm the city the way cattle egrets fill a barnyard at feeding time. Simple errands become lost days. So double-thanks to the gray-haired fellow recently driving his bright-yellow Land Rover through downtown with these two messages plastered on his back bumper: All of us are not here on vacation. If it's the season, can we shoot them?