Originally Posted by You
Actually Princess only asks you to be formally dressed during dinner in the DR and not for any other events. There are many people who change into more comfortable clothing immediately after dinner to enjoy the shows, movie or just lounge around. I'm not really sure when the change took place but it's been that way for quite a while.
In practice, that's what was happened on a few of my Princess cruises in 2002 and 2003, in spite of what appeared in the Princess Patter -- which was that the evening dress code applied throughout the ship, except in designated casual areas -- at the time.
I have not cruised on Princess since 2003, which is why I was careful to state that the policy was "before 2004" on Princess. I would not be surprised if Princess has subsequently changed the policy to reflect what passengers actually are doing.