If it was scripted to the extent some of you think we would absolutely know about it.
Sure, producers have storylines they push, but it's not like they organising morning meetings to tell housemates "today you will be getting proposed to and this is how you should do it" etc. or "today you need to declare your love for Goergina then throw love hearts at Evelyn".
If you were watching live feed the other night Emma and Evelyn were having a nice little conversation about the Diary Room. Evelyn said something along the lines of "it helps you calm down, grounds you, reminds you that it's all a game".
During the same live feed Andy was also talking about how the producers told them before the show that it's "nothing like other reality shows" because the "contestants" are really left to fight for themselves without a script, 24/7, without being able to have proper conversations with producers except through the character of BB.
Sure, Big Brother is gonna push them in the diary room to say the sort of things that will make the storylines flow better - but I highly doubt Big Brother steps out of character or is coaching people on what to say and do. It is certainly not at all on the same level as TOWIE.