Being chemically-bound, whether weakly or strongly, it's hardly free for the taking either. The expression "getting blood out of a stone" springs to mind.
Here's what I sent last night to the Times in response to that trumpeting headline re there being a litre of water per tonne of lunar soil. (One feels that "water" should have been enclosed in quotation marks in the Times's article).
Update: Friday 15:15 pm. Had some further thoughts on the inconclusive nature of the chemistry after reading the New Scientist's feature: Have just sent the following:
"Hmmm. So the signal could have come from water or from the "OH molecule". Leaving aside the faulty nomenclature - OH is not a molecule, but is either a free radical if electrically neutral, or a negatively- charged ion - it seems a bit of a liberty to lump together two entirely different chemical species in this manner. The discovery of H2O would indeed be exciting, even if strongly adsorbed to minerals. But "hydroxyl", presumably as mineral hydroxides, would be an entirely different matter, requiring somewhat high temperatures in most cases if desiring to drive off molecular water, which would then have to be cooled and condensed. Most of the hydroxides of predominant minerals in the Earth's crust - magnesium, calcium, aluminium etc- hang onto their oxygen and hydrogen quite firmly, needing red heat or higher to dissociate into oxides and steam.
So it's somewhat premature surely to report that "water" has been discovered. On the basis of available evidence, none of which can be described as "hard", what's been discovered are oxygen atoms that are bonded to one or possibly two hydrogen atoms with a strong attachment to a mineral matrix given they are able to survive solar heating in a vacuum. Alternatively, and less usefully from the point of view of harvesting lunar water, the signal is picking up a temporary association, ie the turnover model, which would explain why the discovery did not come earlier from study of Apollo-mission rocks"
Update Sep 25 21:17 : See also "How could astronauts harvest water on the Moon" - latest article in New Scientist.