Writing the goal on the TB or the logbook may not even matter much at all. For instance in our case, our bug was clearly marked where it's goal was to end up. Which happens to be Key West for a family wedding which we will be attending the week of Halloween. It started off in early May, seemed to be moving south and made it's way down to Alabama. Sadly it was picked up by daft19 and taken to MN where it now resides. It looks like if it ever makes it to FL, it will miss us.
Sure, it has more mileage, but that's really not the goal and I don't think respectful of the owners at all. IMHO Renegade Knight has the right idea.