I don't agree with Scott that it's a gaping hole capable of
bestowing mountains of gold on players for little effort.
However, it does seem a bit easy. Scaling the return to the civ
level seems reasonable. Perhaps limiting use to cities might
also not be a bad idea.
As Scott points out, I'm loathe to take things away from players, so
I'm not eager to change this even though it could be tuned a bit better.
-- Rich Skrenta <skrenta@pbm.com>