Dave wrote:
I should, of course, have said "incremental cost" rather than "marginal
cost" in my previous post.

Right, but Peter's point is still valid_ that it may cost
more to bill for the data & collect payment than they are
receiving, and the data itself is already paid for ...and
there is enough "common good" benefit that it's not really
bilking the taxpayers even if they don't have the foggiest
idea why they need it.

Charts are expensive, but I don't believe for a minute that
yachtsmen have paid the entire cost of the surveying, much
less everything else. And I don't believe we should, either;
for the same reasons that I don't believe residents of the
area devastated by Hurricane Katrina should bear the whole
cost of rebuilding.

Fresh Breezes- Doug King