Premise:  There exists a community whose top-most goal is to maximally and fairly fulfill the goals of all of its members.  They are approximately as rational as the 50th percentile of this community.  They politely invite you to join.  You are in no imminent danger.

Do you:

• Join the community with the intent to wholeheartedly serve their goals
• Join the community with the intent to be a net positive while serving your goals
• Politely decline with the intent to trade with the community whenever beneficial
• Politely decline with the intent to avoid the community
• Join the community with the intent to only do what is in your best interest
• Politely decline with the intent to ignore the community
• Join the community with the intent to subvert it to your own interest
• Enslave the community
• Destroy the community
• Ask for more information, please

Premise:  The only rational answer given the current information is the last one.

What I’m attempting to eventually prove The hypothesis that I'm investigating is whether "Option 2 is the only long-term rational answer". (Yes, this directly challenges several major current premises so my arguments are going to have to be totally clear.  I am fully aware of the rather extensive Metaethics sequence and the vast majority of what it links to and will not intentionally assume any contradictory premises without clear statement and argument.)

It might be an interesting and useful exercise for the reader to stop and specify what information they would be looking next for before continuing.  It would be nice if an ordered list could be developed in the comments.

Obvious Questions:

<Spoiler Alert>

1. What happens if I don’t join?
2. What do you believe that I would find most problematic about joining?
3. Can I leave the community and, if so, how and what happens then?
4. What are the definitions of maximal and fairly?
5. What are the most prominent subgoals?/What are the rules?