Its a sticky one that DFC.
You have to have logged 3 landings in the last 90days to carry pax.
So if the pilot went up solo no probs they are P1.
If the owner insisted they wanted to see the pilot fly yes the owner then logs P1 and checks the pilot out to there satisfaction. The legalitys of this are under discussion in fact its worse because the owner will presumably charge full whack to the pilot which means they aren't sharing the costs etc. But unless the owner of the plane is a FI the pilot cannot log this session at all. Which means the pilot dosn't have 3 takeoffs and landings logged. So they then must go up solo to log the P1 to meet this requirement.
MJ