What a wonderful idea! You know, RD and I were discussing, how in Cuba, its more valuable to tip them with consumer goods than with money. It never occured to me that the same might hold true for ships.
I was reading at a Disney Cruise board, where there is a crew member posting who says they go nuts for Candy and things they can't get on ship or in port. She said, some guests have even snuck food out of the buffet or MDR and brought that to them which they loved because it was better than what the ship fed them. [I found this part confusing because on Eurodam, I saw the crew eating in the Lido, but perhaps this is not the norm on other ships.]