I think the duck thing is relatively new to Disney. We have sailed with them since 1998 and do not recall ever hearing about ducks pre-Covid. DCL considers the ducks a safety issue as there were reports of people placing them on lifeboat davits, near the anchor chains, and some being found in the plumbing, It is my understanding that if crew members find them they just throw them away. One person did report that she had a large bag of ducks that was confiscated by security before she boarded.