That's certainly good news.
Coons is a deeply, deeply unexciting candidate who doesn't have anything remotely resembling a personal touch.
But that's what union leaders and "community organizers" are for: getting the rank and file to march to the polls no matter how lousy their candidate is.
If they aren't getting the turnout job done, this becomes very encouraging.
Obviously the Dems didn't expect to need a ground game here. OTOH, you may have a lot of Dems who don't like Coons but couldn't bring themselves to vote for O'Donnell so they are staying home. That would kill the Dems down the ticket which would be absolutely delicious, since one of Rove’s “arguments” for having Castle on the ballot was for the down ticket Republicans.