Have you even watched his show? Gavin is obsessed with provocateurs of all kinds. He's an encyclopedia of everything punk. During his Vice years, Vice was constantly pushing the envelope. He being doing these media stunts his ENTIRE career.
So if you've been paying attention, its par for the course. It's who he is. The "omg I can't believe he did that" is Antifa-esque concern trolling.
He also didn't fake getting arrested. He did some little weird intro at the beginning of a show then shut it down abruptly. And, again if you've been watching you could tell he was acting because he did it at like the perfect time and he's a terrible actor.
It wasn't a hoax per se. It was a little "art experiment" as he calls it. It wasn't the greatest art, but whatever.
If you've been following Gavin, he's obsessed with punk history. This is completely out of the 70s era punk playbook.