Final answer:
In 'Seabiscuit,' the trainer Smith deceived the press and the horseracing public by disguising Seabiscuit's training and performance, and spreading false rumors about his health and ability.
Step-by-step explanation:
In Seabiscuit, the trainer Smith deceived the press and the horseracing public in two ways, as discussed in the article. Firstly, Smith disguised Seabiscuit's training and performance to make him appear weak and unworthy of attention. For example, he would keep Seabiscuit hidden during practice races and cover his coat with a dirty canvas. Secondly, Smith spread false rumors about Seabiscuit's health and ability to throw off his competitors. This created a psychological advantage for Seabiscuit as the other trainers and jockeys underestimated him.