This should work, can't test: room flags passed in room info message instead of just 'in-game' state, including 'in-game', 'restricted joins', 'registered only' and 'passworded' flags
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>get-task-allow</key>
<false/>
</dict>
</plist>