Married?

The married twist appeared in Big Brother 2013 where 2 housemates (Jade and Drew) would have to pretend to be married for 1 week. They failed the task and were automatically nominated.

Rewards or punishments
If Jade and Drew went a whole week without anyone reporting to the diary room speculating about the 2 of them being married, they would revive immunity, if someone reported to the diary room and told Big brother that they did not believe the pair were really married, they would be automatically nominated.