You saw this in WoW and other MMOs. People would DDoS a rival during their raid night to cause havok, or if they were going for a world/guild record. People would also DDoS the server if a streamer was on that server. People are weird.

Wow, that's crazy, I had no idea people took WoW to those lengths.

Absolutely in competitive games, or even in MMOs against rival guilds.