The Shark Stadium that was shown being imploded on a news cast is a different stadium than what was shown in previous clips before the implosion.
When Mrs. Murphy is about to announce the winner of the essay contest she states that the winner will not only win an internship in the mayor's office, but that student will also get to implode shark field on Saturday. However, later it is shown that the day the stadium is to be imploded is a school day, not a Saturday. Further evidence of this continuity error is when Woody stops by Keith's office to collect the DVD of the surveillance footage of his house and he says that it's nice of Veronica to help out her dad on her lunch break.
When Woody's (Steve Guttenberg) in the Mars Investigations office, he says Veronica (Kristen Bell) is a "good kid" for helping out at her father's office during her lunch hour. The clock on the wall indicates that the time is 3:25pm however, well past the school lunch hour.
When talking with Mac (Tina Majorino) about Beaver (Kyle Gallner), Veronica (Kristen Bell) opens up her locker without the need of the combination.