I agree, it should not go over the top. I also agree with Carnival about banning ducks with business cards or homemade goods attached. Ducks with business cards is solicitation and one doesn't know what has been put in the homemade goods.
I have heard that Disney is the only line that discourages it. They don't forbid it, just discourage it. I don't see the harm in spreading joy. If other's don't like it, they don't need to participate. Just my opinion.