Carl Block and Alex Cooper both work with Laurie in the publication office of Gordon High's school paper. Like Laurie, they are immune to the charms of The Wave. In fact, Carl and Alex are the ones who convince Laurie that they have a duty as journalists to investigate The Wave and publish what they find.
So what is it that keeps Carl and Alex immune to The Wave? Shmoop thinks that, like Laurie, they both have a strong sense of themselves as individuals. When Laurie, Alex, and Carl are in the publication office during The Wave rally, Alex describes the three of them as "The last of the rugged individuals" (12.48), borrowing a phrase from 31st U.S. president, Herbert Hoover.
Another thing that keeps these guys immune to The Wave is a good sense of humor (and you know that Shmoop appreciates that). They have trained themselves to see the ridiculousness of situations, not to take life too seriously. When Laurie isn't amused by his Wave jokes, Alex tells her, "Laurie, you must learn that nothing is above ridicule" (12.44). And he doesn't stop there: he keeps up the jokes, saying they can start a new group and name it "The Ripple" (12.55). Bottom line: Alex and Carl add additional perspective to the novel, and just plain old help lighten the mood.
One last thing. Think about this: if Alex, Carl, and Laurie had been part of The Wave, the paper might have been used as a way to promote The Wave, rather to provide the public with information on it (and pretty much slam it). Goes to show you how the media can be used and abused in all sorts of ways.