CtoR, how does Mrs Jones and little Johnny flying in from the sticks by a pilot they've never met and know nothing about, in an aircraft they know nothing about assess the risk of such a venture? They can't.
It's not just the pilots who might feel self pressure to "get the job done". The people who utilise these flights are also under pressure to accept whatever they're offered - they want to get to that medical appointment and the service is provided for free so who wants to appear churlish by refusing?
How does anyone who is not a pilot or at least has a passing familiarity with aviation really assess the risk?
Angel Flight is providing a service (and good on 'em for doing it) and the passengers deserve to know the standard of service they're receiving.