“Police only have to believe the knife was illegal. The job of determining if it was legal or not rests with a jury.
This is an important point that few appreciate.”
And one that most people get wrong. The judge determines the law (aside from Jury nullification which I support), the Jury decides the facts.
After a couple of court cases, the police should not be given the benefit of the doubt any longer. The only reason their is any doubt in this case is because the law is confused and vague.