Because of an inflexible schedule, I'll be hitting town no earlier than 4 P.M. for this weekend's game. By design, I'll be doing so without a ticket for the game. (Plan A is to purchase one outside the stadium. Plan B, which would be just fine, is watching the game a few blocks away.) Here's the question: How long can scalpers be found outside the stadium? A few minutes? A half-hour? Longer than that?