If you write example: http:// techcrunch.com/2010/06/12/andreessen-horowitz-to-win-the-foursquare-investor-badge-----/ instead of http://techcrunch.com/2010/06/12/andreessen-horowitz-to-win-the-foursquare-investor-badge/ or even with 1 line it will display the page and not give 404. If someone wants to get your website into trouble he can link to some pages with lines in the url, and google will see duplicate pages with same content and ban will result, what do you think?
No. It will still go to the correct URL. If there is only one page with the information, there is no duplicate content no matter how it is linked to.