Just finished 2 matches in a row with a match manipulator. A really easy way to prevent this would be:
1) Make sure at least 3 queues are popping simultaneously. Stop with this "As soon as we get 10 bodies" thing. This makes rigging the match you're in too easy. To help with this, allow players to phase/play as normal (i.e. switch zones, do whatever they want) while they're waiting.
2) Don't let free accounts participate in ranked sPvP.
3) Don't just retaliate against the obvious bot. There's someone on the other team who put that bot in for a reason, find out who it is and punish them. It's also ridiculous I would get more in trouble for posting a screenshot of the person than the actual aggressor.
Also, at this point, with the introduction of smaller tournaments, it doesn't make sense to allow duo queue. Add a 5v5 mode and a solo mode and use the other formats for smaller groups.