My wife volunteered as an attorney poll observer in eastern N.C. She found the whole operation incredibly disorganized: she had to call all sorts of people over the course of several days just to get trained and she received contradictory assignments and so forth. I've heard other attorneys had similar problems.
The way the barcode thing worked in N.C. is that both Reps and Dems are entitled to have an observer who actually sits in the polling place and checks off the names of people who came in to vote. The campaigns then had "runners" who were allowed to walk into the polling place (I think the limit was three times during the day) to retrieve the lists of people who had voted so the campaign could target GOTV efforts at people who hadn't yet voted. Since I voted early, I never got called, but everyone I know who waited until election day says they got called several times Tuesday.
-WD