Trivia: When the orange dragon scorches the purple dragon to bones on the video game that Greg and Rowley are playing, you can hear the Wilhelm scream.
Trivia: When Colin and Rowley have ice-cream, they never actually finish it. The second the shot cut, the actors handed them to a prop guy who then threw them in the bin. Then when the next shot began the prop guy ran to the closest freezer, which was about 100 metres away, made the ice creams as fast as he could, and ran back and handed them to Colin. This went on for half an hour. Just saying, they could have moved the freezer. This was revealed in the 'Movie Diary'.
Chosen answer: As said in the film, it was one of the kindergartners who explained the whole story to their parents. It would seem that Rowley would indeed be too soft and cowardly to do such an irrational thing.