We've had quite conspicuous "monitoring" in the local Vue, complete with staff banging the door when they come in and out. But maybe this announcement was a response to complaints about bad behaviour in a previous screening?
It's a rare thing to see an usher at my local Odeon. They just take your ticket and point you to the specific screening room. I remember the days they used to show you to your seat with a little torch (like they do at the theatre), do any cinema's still do that?
Has anyone ever been to a crew/cast screening? I went once in Leicester Square and throughout 3 people were stood near the front at the side staring at us all with binocular/detector type things. Throughout the WHOLE film. It was distracting at the beginning but then I forgot they were there. I wondered if this was generally what happened at a first screening.