Final answer:
The Jones family's decision to eat at the only restaurant open after a discussion is an example of decision-making by default or a non-decision, as it was determined by circumstances rather than active group choice.
Step-by-step explanation:
The situation where the Jones family ends up having to eat at the only restaurant still open after a 20-minute discussion is an example of a form of decision-making by default or a non-decision. This happens when the cost of making a decision exceeds the perceived benefit, leading to a situation where the group defaults to an option by necessity rather than active choice. Given the constraints of time or other factors, such as the closing times of businesses or a lack of consensus, the group may be unable to reach a decision through normal negotiation or majority rule, and thus the remaining option becomes the de facto choice.