[pilot_pirx]

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.

[xyzzyb]

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

[pilot_pirx]

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

[mbrubeck]

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...