 Why shouldn't Purnie stop time?
With everything around him in a state of perfect tableau, Purnie hurried toward the ocean. When Purnie had stopped time, the bees—like all the other creatures he met—had been arrested in their native activities, and he knew that as soon as he resumed time, everything would pick up where it had left off. Rather than spoil what was clearly going to be a perfect day, he chose to ignore the fact that he had been forbidden to use time-stopping as a convenience for journeying far from home. He chose to ignore the negative maxim that "small children who stop time without an adult being present, may not live to regret it." With it under his arm he bounded along a dozen more steps, then stopped abruptly in his tracks. Further down the beach was a pair of two-legged animals poised in mid-step, facing the spot where Purnie now stood. It was time itself that Purnie had stopped, not the world around him. The tripon thought Purnie's feat was superb. Purnie ran from pillar to post, trying to see and do everything at once. Purnie's invitation got nothing more than startled glance from the animals who quickly returned to their chatter. The animals stopped so suddenly that Purnie nearly tangled himself in their heels. As Purnie followed along, a leg shot out at him and missed. Purnie shrieked with joy at this new frolic and promptly stood on his head.
 Stopping time consumes massive amounts of energy.
 Small children who stop time, may not live to regret it.  Purnie may be abducted if the animals know he can stop time.  Purnie may not be able to get time going again.  Stopping time consumes massive amounts of energy.