When TV news programs report wars or disasters, the editors rarely use the most horrifying pictures of dead or wounded victims because they don’’t want to upset their viewers. Even so, viewers are usually warned in advance that they "may find some of these scenes disturbing", so they can look away if they choose. But the men and women whose job it is to record those scenes—the TV cameramen—have no such choice. It is their duty to witness the horrors of the world and record them no matter how gruesome (可怕的) and unpleasant they may be. Consequently, it is one of the most erous, exposed and emotionally taxing jobs the world has to offer. Today, the demand for their work is rising, the explosion of satellite broadcasting and 24-hour news in recent years has created an almost insatiable (贪得无厌的) demand for TV information. But major broadcasters and TV news agencies—such as Reuters and WTN—have never had enough staff to meet the worldwide demand for up-to-date pictures, so increasingly they turn to "freelance" TV cameramen. These freelance cameramen are independent operators tied to no particular organization. They will work for any company which hires them, be it for just a few hours or for several weeks in a war zone. But if the freelance cameraman is injured, in the course of the job, the TV company is not responsible for him. The freelancer must survive on his own. "TV will always need hard, vivid moving pictures which are fresh, but these companies feel uncomfortable with large numbers of employees on their books," explains Nik Gowing, once foreign editor for Britain’’s Channel 4 News and now a BBC news presenter. "By hiring freelancers, they can buy in the skills they need only when they need them. It also enables them to contract out the risk," he says. The main idea of the first paragraph is that______.