I noticed the same thing a couple weeks back!
The 302 redirects aren't as "bad" as nofollow tags from what I've heard, still passing some link juice to external pages, according to this Google thread: http://www.google.com/support/forum/p/Webmasters/thread?tid=7ee9dbd3802c2a2a&hl=en
That said, I believe LinkedIn is one of the authoritative social sites from which the engines are considering links, even if they are nofollowed (like Twitter & Facebook).
