Don't tell Blizzard that. They use a tons of free libraries in their flag ship products, including LGPLv3 in Starcraft 2. Im sure they would just love to delay the release date swith a year or two in order to avoid FOSS licenses and rewrite their own XML parser, fonts, or HTML/CSS code parsers.

That is, unless they can do cost-benefit. Some markets is just to competitive that you can't waste developer time in order to be afraid of licenses. The game market is very saturated, but there might be places where you can afford to entertain peoples fear.