Of course it is scripted otherwise people are not that crazy to fight like animals. Also it depends on the season too... Some BB Seasons are more scripted than others like this one (BB7) and (BB5) while other seasons are less scripted like BB4 and BB6. But I personally feel that since Salman is hosting the show they become more scripted as Salman recommends contestants and also gets biased when needed.
In this season they started with the concept of HELL N HEAVEN but when it got failed they unnecessarily created fights and romance in the house. Season 5 was also not doing well in the beginning but then they bring Sky, Amar and Sid. After that everyone knows what happened.
So far I liked Season 6 and Season 4. Those are the best seasons in the history of BIGG BOSS.