What did they get in trouble for in "How to Eat Fried Worms"?
Billy and his friends, like most boys their age, get in trouble regularly for a number of different reasons, most of them minor. In the events leading up to the bet in the first chapter, Tom, Joe, and some others are apparently stealing peaches from a neighbor's tree, and Joe is caught. The boys have to return the peaches, and the neighbor calls their mothers. Then, Tom won't eat his dinner, so his mother doesn't let him go out to play.
When the boys first make their bet, their parents seem to look upon it as harmless behavior, and generally leave them alone. In Chapters 27 and 28 however, when Alan and Joe try to cheat on the bet by tricking Billy and forcing him to announce with a siren before midnight that he has remembered to eat his daily worms with minutes to spare, their parents get upset and make them apologize to the neighbors for waking them up. All four boys get reprimanded for fighting in Chapter 30, and in Chapter 37 Joe gets in trouble for planning to put Billy in the cistern, the one episode of mischief which could have had potentially serious consequences.