I was on BBLB. Have told this story on here before.
A friend worked on the show so we went down to the filming. He ended up getting me to tell Dermot who I wanted to be evicted at the end of the show.
They actually told me what to say. I did it. To be fair, I don't think this was common practice as a) I knew people who worked on the show and b) nobody in the crowd seemed to want this particular housemate evicted, they obviously had to have a fair share of opinions so asked me to step in when they couldn't find anyone.