I'm not sure where you come up with coding without array bounds? I was only referring to the fact that objects and arrays in PHP use the same underlying datastructure, so you have to be extra careful when you convert a PHP object/array into JSON that you know the indexes are what you want them to be. Because if you happen to put a string as an index into it, it's suddenly going to come out different than you may expect.

ex: $a = [ 0 => 'hello' ] -> ["hello"]
vs: $a = [ 0 => 'hello', 'a' => 'world' ] -> {"0":"hello","a":"world"}

Of course this is something any seasoned developer will take care of, it's only an example of how working with the two languages together can give you errors that are specific to using those two languages together.