Raise an Error or Warning upon .ask'ing for more points than the generator can reasonably provide

[jlnav]

Possibility 1: Hint to user that they received less points
raise RuntimeWarning("Requested more points than available. Your workflow/allocation may not operate efficiently")

Possibility 2: Crash upon not providing enough points

raise RuntimeError("Requested more points than available. Exiting...")

I'm leaning more towards a Warning.