You have to ask yourself if people who will actually vote McCain in the official election might be more reluctant than Obama supporters to share their preference with the world. Also, do Obama supporters drink as much coffee as McCain's?
How many Obama T-shirts and bumper stickers have you seen compared with the number of McCain-emblazoned merchandise? Has it been "pretty close in number," or have you seen more Obama stuff? I don't know that I've even seen a McCain bumper sticker or T-shirt, although I saw one guy in the gym the other day wearing a "I think therefore I vote Republican" T-shirt.