Let's see - I'm "Chicken Little" because I don't think OP should take ANY risk for a developer.

No, you're Chicken Little because you appear so convinced that certain parties are intent upon seeing Ocean Pines get screwed in all of this, and, further, so convinced that Ocean Pines will ultimately get screwed in all of this.  I don't think the four commissioners voted for the sake of the developer; I think they did so to start implementing their vision for development in northern Worcester, which means preventing Pennington Commons from setting up a separate spray irrigation system.  That's where I think you're going wrong.  This isn't about serving developers; it's about implementing a vision for development in northern Worcester.

if the potential risk is "likely never to materialize" then why was the developer extremely adamant he was not going to take that risk?

You make a valid point.  Eisenberg was certainly unwilling to commit his client to cover that risk, and I would have preferred that he had.  Still, the four commissioners apparently felt strongly enough about their vision, and confident enough that the risk will not materialize, such that they chose to proceed forward anyway.  They took a calculated risk.  Time will tell whether they were correct in their assessment.

Frankly, I'm at a complete loss as to how anyone can justify making Ocean Pines ratepayers take ANY risk for a developer when we have nothing, absolutely nothing, to gain by taking the risk.

I disagree with your characterization.  The risk has yet to materialize, and, if it does, it will be allocated at that time.  Further, I don't think the risk is being taken for a developer.  I think it is being taken for a vision as to how development should occur in northern Worcester, and in Worcester overall.  Both Worcester and Ocean Pines have much to gain, in terms of overall quality of life and environmental quality, if this vision comes to full successful fruition.

How a more or less self-identified liberal Democrat can justify such a circumstance is even more mind boggling.

More of a moderate Democrat with libertarian leanings, actually . . .