Mocek's arrest, according to the audio recorded when he was arrested, was "for being stupid". The actions he was doing were trying to board a plane with a valid boarding pass but without ID, and taking photos.

An ID is not required for flying in the US. Taking photos is not illegal. The first is a bit surprising to some, and even the second, so I can understand how you may have thought those were a problem, but surely you knew that being stupid is not a crime?

His arrest was so unjustified that he didn't even present a defense at trial. After the prosecution called its witnesses and presented its arguments, and the defense was given its chance, the defense rested without calling any witnesses or presenting any evidence. All the defense did was in closing arguments point out all the holes in the prosecution's claims, and an hour later Mocek was acquitted on all charges.

Rachner was arrested for acts that were not criminal. That in itself is not abuse, since the police can make mistakes. However, they withheld evidence that would have shown they were wrong. That is not upholding the law. That is abuse.