I learned from this post on Language Log that use of commas in a provision of the Bankruptcy Code has become an issue in the bankcruptcy case of the Philadelphia News. Being a veteran of comma-related strife myself, I have a soft spot for such matters.
But prevailing in any comma dispute comes a distant second-best to avoiding such fights. If the meaning of a given contract provision changes drastically depending on the presence or absence of one or more commas, you might want to restructure it.
Updated 12:46 p.m. EST, Dec. 17, 2009: Reader Steven Sholk joined in the fun by telling me about this story on Bloomberg.com, about a “single contentious comma inserted into a paragraph of a United Nations climate deal two years ago.”