Yes, but in this case it's not about readability, but about extremely significant whitespace. Forgetting a space and your code has a totally different meaning.

Whitespace is already extremely significant in programming. "foo[1]" vs "foo [1]" for example.

Depends on language, in Ruby those statements would be identical. But anyway, that's no reason to make things even worse.

In Ruby those statements are the same when foo is bound to an array, but they are different when foo is bound to a function...

And I have found the opposite. Horses for courses.