The pilot in command decides, always
Rightseat operates no flights, judges no weather, and has no say in whether one goes ahead.
Whoever offers a seat is the one flying. That makes them pilot in command, and the only person who decides whether the flight goes ahead.
The platform introduces people and keeps track of what was agreed. Nothing beyond that. If a flight does not happen on the day, that is the pilot's decision and not ours.
So as a passenger you know in advance: an agreement is an intention, not a timetable. That is how small aviation works.