What's the deal with CTP Green slips?

[Rainbow7]

You can put the blame squarely on the middle-aged fools who own Harleys. - See, CTP also covers pillion passengers, so when those 50+ tossers put their saggy-breasted, dough-bodied wives on the back of their shitboxes, then crash while wobbling around a corner at a whole 30km/h, the claim for the pillion's injury is made against the motorcyclist's CTP. Thus, we get pumped because of a bunch of lawyers and accountants who like to pretend that they're Dennis Hopper while they ride down to Berry to go antiquing.

I never carry a pillion passenger, so I don't see why I should have to pay the same CTP as someone who does.