shrewd marketing or spam?

The Chicago Cubs has agreed on a deal with sports apparel maker Under Armour to have ads placed on its legendary ivy-covered walls. The Cubs' Wrigley Park is one of the most traditional ballparks in what is arguably America's most traditional sport. Already some purists are protesting this move.
Reference:
Sullivan, Paul. Cubs Show Tradition The Door With Ad Deal. Chicago Tribune. February 14, 2007. (see here)