A few years ago, I got stung by one in shallow water in FL, and I've been pretty afraid to get in the water since then. The beach where it happened recommended the "stingray shuffle" to scare them away while you were walking in the ocean but I was in below-knee-deep water and thought I would be ok. My wound hurt A LOT for about 24 hours (and I'm not a pain wimp), and it took several weeks for it to heal.
Do they have any warnings in the area about the stingray shuffle?
Carnival Ecstasy - January 2013
Carnival Legend - May 2012
Carnival Sensation - May 2011
Carnival Triumph - October 2009
Premier Cruise Line, Starship Oceanic aka Big Red Boat - September 1986
Costa Flavia - May 1976 (high school graduation cruise!)