I know that Borat is not the greatest of all movies but I have always wondered if scenes in the movie where he appears in public, staying at the Jewish house etc. have been staged and participants were well aware of what will happen next?
No, evidence shows that the movie was made in a documentary type of way, but the studio tried to cover itself with releases. Lawsuits filed against the movie, actor, and studio failed, as there was no evidence that the people were manipulated. There was no statements in the lawsuits by either party that the scenes were scripted.
Other individuals threatening lawsuits against Sasha Cohen and 20th Century Fox include two etiquette coaches, Cindy Streit and Kathie Martin, from Alabama. Both women are depicted in the film giving etiquette lessons to Cohen's character during a dinner party. The dispute here is that both women were offended by the comments made by Borat regarding slavery, a demeaning comment made against one of the dinner party guests, and the bag of excrement handed to Streit. The women claim that this film has single-handedly ruined their etiquette businesses and, as with the Fraternity boys, demanded their likenesses be removed from the film prior to its release. As with the Fraternity boy case, it was decided that the film would be released to DVD as scheduled and that 20th Century Fox was under no obligation to remove the women's images from the film. Both women signed a release for the company in which they agreed not to file damage claims against the producers. From a lawyer's standpoint, the parties involved should have read the agreements more carefully.
[Another] scene in question show the two boys, obviously intoxicated, making obscene racist and sexist remarks. The boys claim that the film crew told them this documentary would not be shown in the United States, and that the film crew is responsible for taking them out to a local bar to get drunk prior to shooting. The representatives for 20th Century Fox claim that the boys knowingly signed a release to hold the company harmless and the behavior of the two boys was not the result of anything said or done by members of the film crew. After hearing both sides of the testimony a Los Angeles Superior Court Judge ruled that he would not halt the release of Borat to DVD, nor would he require Fox producers to remove scenes involving the two Fraternity boys.
This is not to say there wasn't any staged scenes, but a good portion was filmed in a truly unscripted manner.