I have done any number of Ex EUs. I always (at least in recent years) try to book a last leg that I can use. e.g. on to Stockholm a day or two after the long haul leg back to London with the intention of using it. However, I generally book 2-4 weeks ahead, and things change. Meetings get rescheduled, others elsewhere take precedence. Net effect? I have dropped half a dozen last legs over the last 5 or 6 years. Generally it isn't my intention. Lordie if they are going to rule that effectively, if my plans change and a drop a leg, I should pay an undefined (until after the event) penalty to an airline because I have scurrilously defrauded them...what a can of worms!