Every so often, a disgruntled college graduate sues her school on grounds that her tuition payments did not land her the good job she was expecting when she started there. Courts invariably throw out cases like hers. They are, however, willing to entertain suits against trade schools (those that teach skills such as welding and computer repair) by guarantee that make the same claims about inability to qualify for jobs that use the skills they learned in them. Why the difference?