You might look at it like this: Suppose you have votes on paper ballots, and you pile all the paper ballots in room one. Then, you make a copy of all the ballots and put the stack of copies in room 2.
You then leave the door open to room 2, so that people can come in and out, replacing some of the votes in the stack with their own.
You could have some sort of security device that would tell you if any of the copies of votes in room 2 have been changed, but you opt not to.
"The Truth About the Rob-Georgia File" (same author) has an interview with one of the folks who was responsible for deploying this system, who tells a story that lacks basic security measures in just about every way you can imagine. This story pretty well undermines the first story, since clearly this company couldn't find its ass with both hands: they don't sound smart enough to rig an election.