Lasiorhinus,
You're looking at the wrong regs in respect to the original posters question. He asks whether a passenger can be carried on a dual flight once the trainee pilot has passed the GFPT, in which case the instructor is pilot in command not the trainee.
The regs detailed in post number 5 give the answer. The two points of interest however, are the definitions of both the emergency procedures and low flying.
Here's an interpretation - provided you're not below 500 feet AGL (normal VFR requirement over non-poplulated area) then are you conducting a low flying operation, wouldn't have thought so. Given that, if your instructor elects to have you practice a descent at idle power whilst conducting a couple of drills, with the descent in question not below 500 AGL, I'd be hard pressed to argue it's a practice forced landing since theres no landing involved and it doesen't even sound like an emergency procedure...
On the other hand, if your instructor pulls the engine and makes you land in an unprepared paddock, then you've conducted both emergency procedure practice and low flying, definitely no pax allowed on that one.
I like the CAO 40.1.0 - 10.3 that you've pointed out, that's a classic but there's surely a contradictory regulation somewhere else that will cover it.
