Since this is a family oriented board I can't really say what should be done to those owners but an interesting site for all to read is here.
http://www.workingpitbull.com/activities.htm
and for those who don't want to spend time browsing the following pages are good though I do warn that they aren't for the faint of heart.
http://www.workingpitbull.com/dogfighting.htm
http://www.workingpitbull.com/whydodogsbite.htm
http://www.workingpitbull.com/fatalbook.htm