More specifically, what usually happens is that you give a regular advertiser a few freebies now and then, e.g. for every USD 10,000 of advertising we'll publish three press releases you fax us. To keep relations well-oiled an friendly, a corporation will wine & dine the journalists assigned to cover it, with little take-home gifts after coffee and the last digestif -- anything from a basket of the company's food products to a pair of airline tickets.
Oh you mean like Print media journalist booking economy tickets on BA and amazingly when they check in the get upgraded, thats called News management and BA have been doing it fo years.