[ExI] Trying for a minimum technical comment

[Adrian Tymes]

On Tue, Dec 18, 2012 at 11:04 AM, Mike Dougherty <msd001 at gmail.com> wrote:
> I'm not sure we have any simpler
> "tech" than digging a really nice hole in the ground.

Said with tongue in cheek, given all the complications you just
pointed out with that, right?  ;)

One major thing you missed: water tables.  Underground spaces
would get flooded easily (and irregularly), in many places people
currently choose to live (and thus where you'd have to dig to get
people to move in, since most people won't move away from
establish supply infrastructure, and are correct to refuse to).