You could put up your own little stand advertising various sites that are against either their religion or Christi-SCAM-ity itself, or both. This site is a good place to start, along with jwfacts. Or, Joy of Satan (or Exposing Christianity) in conjunction with this site. Your message is simply to advertise the truth about their religion and give people a place to start researching on their own between what the washtowel says and the truth. And in the event this net neutrality thing leads to Internet II, you would start printing simple materials yourself and offer them to give an opposing viewpoint--it's your choice which source you choose to get your materials from.
That, ultimately, would do more good than disrupting the carts. Because you would be disrupting their message by giving people a second option. Most people taking the littera-trash are looking for alternative viewpoints, and a second option would make more sense. If people can research, they will not choose jokehovianism. Even with Internet II, which is like having a secondary cable system, making a simple presentation that the jokehovians have been wrong since 1874 or that Christi-SCAM-ity shares much in common with communism, or showing people that jokehovianism shares much with Judaism while proclaiming to be fully Christian, might prevent some from falling for the scam.