Sam, the para is intended to kill off the airtaxi idea.
I say I sm going Rochester to Bodmin, you want to go, we agree to split the costs - say 10% to je 90% to you - 100% legit.
Now if you come to me and say "I want to go to Bodmin, 90% to me and 10%" to you that can be legit but ONLY if I fly to Bodmin on the agreed day even if for some reason you decide not to go. I seems a good way to spot people setting up non-legit airtaxi services.
Seems to that what will control this may not be the aviation authorities but the insurance companies, if they say you are not civered you would be foolish to do it - renters would probably ban some types of rental without renters having their own hull insurance.
The FAA have something similar to this in the bill that just passed congress a couple of weeks back - we are into the 90 dats for the FAA to propose the rules, it will be interesting to see what they put in place.