First of all you don't need it. Secondly, the regulation even states that the right is granted automatically anyway. Technically, the rule had been in place for the past 45+ years anyway - even when there was mandatory military service! - so it doesn't make any practical difference.

At the moment, the law has no teeth since they cannot stop anyone from just leaving without return ticket, and nothing happens when you return. Of course it would be very easy to change that, and that's the reason why it exists.