If he's prosecuted or not isn't the point
FACT are not complete idiots. This tactic used in the US, is as much about frightening and intimidating people than successful procecutions.
Lots of headlines and pictures of some everyday person in handcuffs, is what they are after. The procecutions are useful but secondary.
Also, so what if Google etc bring up copyright material or not. These are all selective prosecutions. They are not going to go after Google, so the issue doesn't arise.