I am confused? SEIU members for Scott Brown? Huh?
There are a number of FR threads about it and some links.
The man featured in the youtube is in the lower left side of a couple of pictures here. He is in a wheelchair.
http://spectator.org/blog/2010/01/15/purple-for-brown-seiu-member-s
http://mainstreetradical.com/2010/01/16/some-seiu-members-support-brown/
http://www.youtube.com/watch?v=_HbcxXvvf_s&feature=youtu.be
http://redmassgroup.com/diary/6658/wow-purple-shirted-seiu-members-holding-signs-at-standout
http://michellemalkin.com/2010/01/13/seiu-affiliated-union-endorses-scott-brown/
http://www.freerepublic.com/focus/news/2429972/posts?page=159#159