I agree. Technically it's against the rules but I don't think you'll be caught for it.
We've got the same situation this upcoming weekend. Four of us are going to participate in an aeros competition about half an hour away from our home-base. So the (two-place) aircraft needs to be positioned to this other airfield, and be flown back to home base after the competition.
Nobody needs these ferry hours for CPL/hour building, the flight is not a challenge, nobody is going to make a sightseeing detour. It's just a quick straightforward hop from one field to the next. So we're just going to split these costs four-way, and the ones flying the plane are chosen based on what's convenient in respect of where people live, where cars are parked, hotels and such.