Approving on a node proposal you aren't on? Probably bad.
Approving right away on the first node proposal of the round late in the game (Node5), just because you're on it? Possibly game losing.

Look at the following example:

It is node 4. The hackers have hacked two mission nodes and the agents was successful in one. The hackers just need to get one hacker on a mission to win.

Players A, B and C are agents. X and Y are hackers.

Player X is proposing now and proposes a mission of X, A, and B. (If this mission occurs, X will hack and win the game). Players A and B have come to trust each other but do not know whether or not if A is a hacker or not.
People vote for the node mission.
The hackers, X and Y vote yes.
C is not on the node mission and knows it will fail (because since he is an Agent, there are only two other agents, so three other people in the node mission must include one hacker).
A is smart and votes no.
B is not so smart and votes yes. The mission occurs. X hacks the mission node. The hackers win.

What’s the lesson here?

Often in new player games you will see A and B BOTH voting yes here.
Now let’s look at what happens if A and B are both smart and vote no.

X and Y vote yes, ABC vote no, the proposal fails.

Why did Y vote yes? If he was an agent, voting yes on a 3-person mission that he is not part of guarantees that a hacker is on the mission, and thus guarantees a loss if it occurs. Therefore, he MUST be a HACKER.

Player Y was outing himself as a hacker to vote yes on this mission! Not only that, he was showing that the other hacker was ALSO on the mission.

In order to 'catch' him, players A and B need to BOTH vote no! If they do this, then they know:

• Y is a hacker.
  
• X, A, or B is the other hacker; therefore, C is an Agent.

That is a massive amount of information to have gained from a vote. You gain this information by voting against a node mission proposal.

It was a risk for Y to approve on that node mission, outing himself in the hope of winning immediately if A or B is an idiot.

Often, especially late in the game, it is correct to make a series of 'test' proposals, trying to see if a hacker will out himself voting for it. You need to vote against it enough times, that if he does out himself, it is on a failed vote, not a successful one.

So, hackers have an incentive to 'act' like an agent by voting no on these missions. This opens up opportunities for double bluffs. Does a hacker vote yes on the mission that actually has three agent members, hoping enough of them they will vote no? They will then 'out' themselves to show that the other hacker is 'innocent' and thus get him onto the final and critical mission. When everyone is playing at an advanced level like this, the voting becomes extremely interesting.

Often, it is correct to propose the combination you THINK is the agents, vote it down, and then repropose it and vote yes. (Or even do two test proposals first). If everyone votes it down, there is a greater chance that it is correct! The hackers know if its correct or not, they know whether they want it to happen. Lots of yes votes in a critical situation means people are confident, which means it is more likely they are confident because they are hackers and they actually know for sure what is up.

Earlier votes are less critical, and the first one is fairly random. Its preferable to be on this first mission yourself of course, to increase the chance of success, but its less critical overall since time is left. You generally need to have a failure or two to set up 'one of X or Y is a hacker' scenarios in order to figure things out.

It’s interesting when you get two hackers on a mission. Do they both hack and give away that they were BOTH there? That’s terrible. What they really want to do is get ONE hack.

Therefore, the following convention could help the hackers:
If two hackers are on a mission together, then if one of them was on a previous mission, he will use the same action he played in the earlier mission. (If he hacked before, he will hack again, and the new hacker should hide. If he hid before, he will hide again and the new hacker should hack). This avoids headbutting for the hackers, provided that one of them had been on a mission before.

Of course, once this becomes the convention, the meta-game, and you get those one-hack missions, you have to ask: are we sure that those two aren’t BOTH hackers, who coordinated effectively?

I hope this helps your play, and helps your group to reach a state of playing MINDNIGHT at a high skill level. It is very interesting and deep once you get past newbies acting erratically!

As a hacker, is it better to hack a mission that you are on (let’s say you are the only hacker on it), or is it to play safe and gain trust?

In general, the hack is a better result. Hiding is only useful if it gains you enough 'trust' from other players. However, as you go on future missions and they are all failing, that trust can erode quite quickly. This is especially true if people are pretty mistrustful of even a successful mission. In this case you almost certainly want to hide.

Whether the mission is large or small is a significant concern. Hiding on a 2-person mission (in 5 player), and then getting onto the 3-person mission as a result and hack it, can be pretty good. You give away more information by saying 'one of these two people is a hacker' than 'one of these three is a hacker'. So, it’s definitely better to hide in a 2-person mission than a 3-person mission. (And for higher player counts, increase these numbers to the appropriate levels).

However, if you ALWAYS hack every mission, then this will make you suspicious.

Therefore, it is really a game theory problem. hacking is the better result, but you need to hide enough that they don’t just suspect you all the time when a mission fails. If you hide too much, then hiding will not buy you much trust. ('Last time he was on the mission and it succeeded, but he was still a hacker, don’t trust him this time').

So, what is correct? Hide sometimes, but hack more often. Hacking pretty darn often is probably correct, but you have to mix in just enough hides. The less often you hide, the more effective it is when you do.

Hope this helps you see the in-depth mechanisms and elements that will turn your weird games, into awesome deduction fevers.

Cheers,
Franches