I don't usually worry, but. . .

Remember this post with the pic of the boys having a carefree play in the stinger enclosure. Here's a recent picture (plus story) of the very same singer enclosure. Not so carefree as we would have hoped after all.
I've always kept a careful eye on the water when we swim in the sea because crocs are a possibility, although their habitat is supposed to be the river estuaries. That is why they are called estuarine crocodiles, although most people these days just call them 'salties'. The possibility of a croc or two inside the enclosure puts a whole different complexion on things. Even a small one would be deadly to a child. Our estuarine crocodiles are extremely dangerous and aggressive when hungry. They also grow to a huge size and have been measured at over 6 metres (20feet) long.
We have another croc species. The freshwater crocodile (or Johnstone River Crocodile) which is a much smaller, shyer and less dangerous animal. It eats turtles and fish in northern rivers, but it isn't native to our part of the country.
One thing is for sure, we'll be swimming in swimming pools in future and maybe give the beach a miss.