Winning here corresponds to getting the most expected utility, as measured from the start of the problem. We assume we can measure utility with money, so we can e.g. put a dollar value on getting rescued.
1) In the smoking lesion problem, the exact numbers don't so much matter as the relationship between them: you are simply choosing whether or not to gain an amount of utility or to pass it up.
2) Defecting on a cooperator in a one-shot true prisoners dilemma is the "best" outcome, so this is exactly right. See this story.
3) In the hitchhiker example, we might say that we have a negative $1,000,000 value associated with being stranded. This exact amount is usually not specified, the assumption being that this is a large negative amount.
Thus the outcomes are:
- We don't pay and are stranded in the desert, -$1,000,000
- We don't pay and the driver took us back to the city, $0
- We would have paid and are stranded in the desert, -$1,000,000
- We pay and the driver took us back to the city, -$100
Of course, the middle two bullet points are logically counter to the problem (assuming an open source setting), so the winning decision theories here lose only $100 as opposed to losing $1,000,000 (dying from being stranded in the desert).
Edit: changed utility -> expected utility.