Getting swatted is a new thing that trolls do to people who stream their gameplay. Basically as the streamer is playing, the troll gets a hold of your address, then alerts the authorities about a fake bomb threat at the streamer's address. That's why the SWAT then raids your place. So the guy wasn't surprised because he knew it had happened to other streamers. Actually, the last famous streamer this happened to, he and his girlfriend were charged because they were in possession of marijuana. Pretty crappy.
Yeah it's anonymous. Honestly I'm not sure. It might be an "answer every case no matter what" situation. But I'm not positive how bomb threat scenarios work. There was a guy in my apartment complex - two apartments down, actually - that got caught trying to make a bomb. The guy that wanted to hit the New York subways. He was unmarried and buying chemicals from salons and stuff. The crazy thing is, my mom looked out the window and saw a black, unmarked car that we'd never seen before. She was like, "man, that think looks like something the FBI would use!"