Love CoffeeScript, but yeah omitting parens makes it hard to read in this case. I follow Visual Basic convention. Use parentheses when using the return value. In this case, the constructor function returns an object. Omit parentheses otherwise, i.e. using a function as a method (no return value).

All I can say is you get used to it, and it encourages you to write in shorter sentences, which results in more readable code overall.

What else would it mean?

I can understand what it means, it just takes slightly longer to comprehend without the parens providing a visual cue that it's a function call.

It only gets worse with nested function calls:

    item = new Item title: new Title "Awesome", id: 2

The syntax isn't ambiguous, but that doesn't mean it's easy for humans to parse.

In a language where there are two drastically differing ways to express the same idea, it could mean anything.

How are we having this conversation in English, then?

Well, it took about 8-12 years of practice for me to be able to do it correctly, and at least twice that to achieve my current proficiency. So when I have my choice of designed languages, I'd like one that tries to learn from the failings of the organic ones.

It could easily mean that item is a 2-tuple.

item = (new Item title: "Awesome", id: 2)