We have one of those DVD rental stands in San Diego, too. Unfortunately, there is not one in O'Hare, so I have never used the service. It's a pretty reasonable price, though, if there is a place to return it at your destination airport.
Bicardi - I don't think that the movies are edited for the in-seat video (I assume you were on AA for dfw-eze). I've seen some things on the First Class videos that I can't imagine them leaving in for the main screen, and aside from having violent scenes/foul language/etc, they are not "touched up" like the main screen movies. For example, when "Liar, Liar" was shown on American, the main screen showed airplanes with the Tower Air titles removed, while the armrest video had planes that had the titles on them. Since they are not edited for content, some people and/or companies feel a moral responsibility. Just as WalMart policy is to not sell R rated movies to people under 17, so too did this particular employee feel an obligation to ask your parents for permission before letting you see an R rated movie. You and I have no problems watching them, but I know people whose parents do not approve of them seeing R rated films, and those parents would appreciate that the FA asked. I don't know whether your experience was the FA's decision or AA policy, but I have never had any problem getting my movie selections.