Also on this type of flight there is usually the human factor element of the pilot being under pressure to complete the mission. Non aviators often do not understand that flights sometimes have to be cancelled due weather etc. It's best to explain right from the onset that it might not go ahead and ask the passenger(s) what their plan B is. This primes them up if you have to cancel on the day.
I used to warn my prospective passengers with the adage "time to spare, go by air"