"Nevertheless, in a single game, the best strategy is to snitch because it guarantees that you don't get the maximum jail term. "
Huh? That isn't correct is it?
Snitching is best because it gives the highest payout regardless of what the other person does (snitching strictly dominates not snitching).
If the other does not snitch and you do, you go free.
If the other person does snitch, you should as well, because it gives you 3 months instead of 6.
Not really. The sentence says that the reason you defect is specifically to avoid the worst possible result. This is bad logic. The reason defect is considered dominant is because, regardless of what the other player does, your outcome is better if you defect. It is a very different statement.
Huh? That isn't correct is it? Snitching is best because it gives the highest payout regardless of what the other person does (snitching strictly dominates not snitching).
If the other does not snitch and you do, you go free. If the other person does snitch, you should as well, because it gives you 3 months instead of 6.