I just got back from there two days before the first attack! I only went snorkelling once (it makes me feel sick and a bit panicky) but DH went every day and was laughing at me for not wanting to go too far out from the pontoon!
About three days before we came home I overheard two English couples booking a day out at sea on a private charter boat, so they could snorkel out at sea rather than near the coast. One of them jokily said to the rep 'There are no sharks out there are there?'
She said 'Oh, no. The diving trainers all say they they've been here 20 years and they've only ever seen small vegetarian sharks.' 
I bet those people's bowels have gone a bit loose at the thought of what they did now.