I wouldn't do them with non pilot pax.
There is of course nothing amiss by showing that if you reduce the engine power to idle the machine will not plummet earthwards into the busses full with nunns but there is little to be gained by demonstrating your ability to do a PFL to your passengers (the vast majority of which will have not a clue anyway)
Most bad aviation incidents will have a preamble along the lines of: 'Look at how well I can do this etc'
Regarding windshear etc below 500' and the need to go that low to prove you have set it up correctly, I'd say that if the spot is that tight it will probably pay to give yourself a bit more margin.
FD