I suppose it can get a little silly when you mix closures without arguments and the logical 'or' operator', e.g.:

    // prints 'true'
    println!("{}", true||(||true)()||(||true)());

Of course you wouldn't actually do this unless you're being intentionally obscure. Another favorite of mine:

    // prints '()'
    println!("{:?}", (||||||||||())()()()()());

But I can't recall ever running into such silly code, in practice the closure syntax and logical or do not lead to confusion (imho, ymmv).