The issue with setting aside cabins, is that which ones do you set aside? If it were a strict 25% thing, do you set aside 25% of the inside cabins? What about those that want a suite???
It would be a logistics nightmare trying to keep it all straight. I think the cruise lines do a great job accommodating everyone. How they clean a smoked in cabin so well is beyond me. I've never had an issue. And since my last 2 cruises were on the newer ships, even the casino has smoking and non smoking tables. Which is great.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14, Freedom x 2 6/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013