I attempted to open the file in excel; raised no errors. 

In any case (regardless of Microsoft-concerns), I am glad to see a discussion started and possibly some concern that an update might be useful to the community (it would certainly cut down on the number of stack-exchange posts about this very topic). I certainly would put my vote to have csv handle the NULL byte, in the same way as python does natively. 

Thanks for you time. Oh, and since you are one of the author's, thanks for writing/working on the csv module, VERY USEFUL. :-)