What a good idea
I think it would be cool and cruel to NOT tell the housemates that they are all up at all

It would be like, say, "Big Brother house, this is Davina... blahblahblah... Dave, Shabby, and Caoimhe (for example). The lines are closed, the votes have been counted and verified, and I can now reveal that the 4th person to be evicted from the Big Brother house is... Steve!" Just to really catch them completely off guard