Most of these deaths occurred on unguarded beaches apparently. Yesterday, after being in the Rodopi for a week, i was desperate to get into the sea again at Burgas Beach, to my surprise there was a red flag although the sea was flat and calm with just the odd breakers rolling in. The Lifeguards were allowing adults into the water so off i swam out about 50-60 meters, but when turned to come back to shore you could feel the tremendous pull out into the sea, I've never in 10 years felt such a rip on this beach and could imagine how a poor or non swimmer could easily get into diificulty. At first glance the beach, in a large tideless bay, wouldn't be effected by such a rip-tide (if that's the correct description) which poosibibly gives a false sense of security/safety.
I did read in another article that most tof the fatalities on the coast are foreigners or natives from inland on Holiday.