Gene sees the fight and is reluctant to join it; he even goes so far as to pretend that he has just remembered something else he has to do in order to get out of it. As with most other events at Devon, though, he is pulled in by Finny and peer pressure. This is similar to the trial scene, where Gene really doesn't know what's happening but he joins in anyway.
The betrayal of the snowball fight is minor, of course, in comparison to the betrayal at the trial. Still, it is there, as a preview. As with the trial, during the snowball fight "loyalties became hopelessly entangled. No one was going to win or lose after all," (p. 154). Just as in the trial, no winner can truly be declared. In the snowball fight, the sides are too muddled for either one to win. In the trial, Brinker's aim is reached, but it leaves everyone worse off than they were before they knew the truth; especially Finny.
As was mentioned in the previous post, Gene initially does not want to join in the trial, which is similar to how he behaves when he first sees the snowball fight. However, Finny and the other boys pressure Gene into joining the game—just as he is pressured to participate in the trial. In the middle of the snowball fight, Gene recalls that Finny began switching sides during the game and the boys could not figure out who was on each team. Knowles writes,
"Loyalties became hopelessly entangled. No one was going to win or lose after all" (82).
Similarly, at the trial Gene's loyalties are gradually being exposed, but the process is interrupted by Finny's confusing testimony. The boys do not know what to believe and end up searching for Leper in order to get his perspective on the event. Also, Brinker quickly loses control of the trial the same way his "sense of generalship disappeared" during the snowball fight. At the end of the snowball fight, Finny is overwhelmed by the boys' snowballs. In comparison, Finny also becomes overwhelmed after realizing that Gene purposely shook the branch.