Some fuckwad started multiclienting (probably with a proxy, I set my multiclient limit to 1) to go spy on both teams in arena, stay hidden, and just idle there when everyone else is dead, not only preventing people from playing the next round, but also putting the server into infinite overtime. The arena round won't end because there are still players alive in both teams, and apparently AFK kicking is clientside, because said fuckwad can stay there for hours. (Maybe not literally, but I wouldn't be surprised if it was the case)
Maybe the right thing to do would be to put AFK checking on the server side, and force someone who doesn't move for more than 30 seconds into the spectator team. My immediate reaction instead was to decide that overtime shouldn't last forever on arena, so here's a plugin for that.
What it does
This plugin will force the arena round to end after 30 seconds into overtime. I picked that number for no particular reason.
Install
Download the attached .gml file, and put it into your Plugins folder
Server side plugin (will work for hosts, not joining players)
Built for 2.9.2