Why does Java have an "unreachable statement" compiler error?

I often find when debugging a program it is convenient, (although arguably bad practice) to insert a return statement inside a block of code. I might try something like this in Java ....

class Test {
        public static void main(String args[]) {
                System.out.println("hello world");
                return;
                System.out.println("i think this line might cause a problem");
        }
}

of course, this would yield the compiler error.

Test.java:7: unreachable statement

I could understand why a warning might be justified as having unused code is bad practice. But I don't understand why this needs to generate an error.

Is this just Java trying to be a Nanny, or is there a good reason to make this a compiler error?