This situation is also complicated by the logging of P1/S, or Pilot 1, supervised. I've only really seen this in the UK, mainly on LPCs. The theory is that if you're rated and legal (so your TR hasn't run out yet), and you pass the LPC, you were technically in command, but under the supervision of the examiner - it wasn't instruction, so it doesn't count as dual, but the examiner has ultimate authority in the cockpit, so it doesn't count as PIC.
As Sasless points out, what if I hire an aircraft at one field (or borrow a friends), then fly to another field where I pick up an examiner or instructor for an hour's flying. I've signed for the aircraft, but the other bod is in charge while I'm under instruction. This would be a situation where I'd probably put P1/S in the logbook.