Just a thought.... Flying for a regional airline, we carry lots of passengers who do fly regularly. And 99% of passengers, if not flying regularly, will have flown before. As a passenger, it must get really irritating to hear the Capt or FO give a welcome speach, and then harp on about the Cabin Crew giving a very important demonstration on the safety aspects, and if you could just listen to them, after all it is for your benefit. Capt signs off, then Cabin Crew get on the PA, and say "We're here for your comfort, but primarily your safety, and we're now going to give you a demonstration of the safety aspects of this aircraft, and your attention would be appreciated".
Cabin Crew don't harp on about what we're doing in any of their PA's...."LAdies and Gentlemen, Capt XXX and his/her crew would like to welcome you on board this flight to XXX. The Flight Deck are currently going through the before start checks, and getting the weather, and then we'll be on our way. In the meantime, we'd like to give you a safety demonstration..."
For those that do fly regularly, they've heard it all before, and being told twice every flight that they must listen to the safety demonstration etc must get right on their nerves. And for those that don't fly all too often, they'll probably be so excited about going in a metal tube in the sky that they'll hang on every word anyway and give cabin crew their upmost attention.....