Favourable Reviews

The Hitch Hiker's Guide to the Galaxy is a powerful organ. Indeed, its influence is so prodigious that strict rules have had to be drawn up by its editorial staff to prevent its misuse. So none of its field researchers are allowed to accept any kind of services, discounts or preferential treatment of any kind in return for editorial favours unless:
a) they have made a bona fife attempt to pay for the service in the normal way;
b) their lives would otherwise be in danger;
c) they really want to.

Excerpt from
Chapter 5
So Long and Thanks for all the Fish
Douglas Adams