I think the problem might be a deeper problem.

The writer of the article is asking generally about how a system's rules can be exploited to the point that the original intention of the system is no longer achievable. The sortition is also a system with rules, therefore it can be exploited. As soon as I saw the rock-paper-scissors, I remembered a competition some time ago where different bots played rock-paper-scissors against each other. Now the best bot exploited the reality of the seed number generators, compiled a database of sequences to find which seed the opponent was using, and so on.

So even sortition might be exploitable.