I pass the infamous crodile lake each evening on my way home and I see crocodiles every time. However I very rarely see them in the morning on my way to town. They have been encouraged and enticed by the teenage boys who feed them chicken on a rope -while tourists watch and pay the boys for their trouble. I have seen up to 7 crocs at one time in this area.
When I lived in San Pablo we had a croc that lived and hung out right by the house - only a chain link fence between him and us.
They are indeed prevalent - but they typically stay in the lagoons and canals where the water is murky.
With their habitat being encroached upon and destroyed the existing crocs are now easily spotted. When I was a kid it was a very rare occurance to spot a croc.
As always common sense should prevail when in the vicinity of potential dangerous wildlife.
On another note, the sea is teeming with sharks, sting rays, jelly fish etc - but it doesn't mean that you are in imminent danger each time you choose to take a dip.
If you go and visit the jungle you would probably be very lucky indeed to spot a venomous snake or majestic jaguar -but they are there and one needs to be wary.
For the most part unless you go looking for the crocs (as a tourist) that is the only way you are likely to spot one.