Did they? At worst they have tilted the field slightly -- they gave you a disadvantageous position in the swamp, a PITA client during the escort mission, and annoying roles to play during the Mafia party. None of that would be easy to prove as deliberate, either.
They've done a pretty good job of toeing this line, being disruptive enough that it was meaningful to us, but not enough that we'd be able to get anywhere with a complaint. However, these events form a pattern, and if the proctors suddenly try to disqualify Hazou with a -30k point penalty based on flimsy evidence, the pattern will be an argument against their neutrality in the matter.
On that note, I wanted to briefly discuss the possibility of Hazou being DQd here. To be completely honest, when I wrote the Pressure Cooker plan, the failure mode I was most frightened of was Akane being identified and blamed for the events unfolding as a result. The reason is that she's a civilian-born ninja with no backing, and it wouldn't be that difficult for Mist to bully her.
On the other hand, Hazou is the Hokage's favourite adopted son, and said Hokage is in the middle of sensitive negotiations with Mist leadership. The proctors can't just DQ him arbitrarily; doing this immediately turns into a diplomatic incident with both Jiraiya and Mist's ruling elites becoming involved. I'm pretty sure none of the proctors want to step into that minefield.
So let's say it comes to it anyway. Even if Hazou is ultimately disqualified, Jiraiya will have extracted some concessions in return; the proctors' history of tilting the field against us makes it easy for him to paint the proceedings as a witch hunt. Especially given that we performed so well in the third event, it would be easy to claim that Mist is afraid of us dominating the exams and humiliating them this way. And if the event is completely derailed, they'll look incompetent as well, and perhaps desperately trying to find a scapegoat to for their failure. Ren might push for the DQ anyway if she really needs it to save face, but it will cost her in the negotiations.
And ultimately, even if Hazou gets DQd, Keiko, Noburi and the rest of the SuperTeam are still in the exam, and untouched by the mayhem of this event. They'd be very well positioned to reach the tournament. I think this, is also a very acceptable outcome.
In conclusion, if we can have Hazou do something obviously and visibly intended to
help the situation, then a subsequent DQ might not be so bad.