Most locals know better than to cross Robin, the friendly fixture at 7th and Montana with a taste for Tai Chi, but I say go ahead and cross her ... it can be rewarding. Just ask Judy, the Neighborhood Crossing Guard. Whenever the mood strikes her -- and it struck her this morning -- Robin brings Judy a steaming Grande Drip, just because it's a nice thing to do. Today I decided to secretly trail along behind Robin and her husband, Screenwriter Nat, just to see the hand-off in action. To my surprise, by the time I arrived at Judy's post, Nat and Robin were gone, Judy seemed to have guzzled down the coffee and was already talking to another couple. Perhaps they brought her some pastry ...!