I've had no problems with bring my own wine onto two NCL cruises, a Med cruise on the Dream in 11/01 and Hawaii on the Star in 9/03. I do remember reading before my last cruise that they were more strict on cruises out of Miami. It wouldn't surprise me if the confinscated liquoir, but if you're bringing fine wine that isn't on the wine list I doubt you'll have a problem. If you do, talk to the wine steward or to a maiter'd.
Change in policy? I'd still give it a try. Worst case, you have to bring it home. If it gets snagged, I'd talk to the wine steward or a maiter'd in one of the restaurants. A nice tip would probably help.