The group will have arrived by 14:30 and will be waiting for me for over an hour. Landing at 16:11 is already asking them to wait too long, but now landing at 17:00 is an overstetch.
In past, LH, OS, AF, LX and LO allowed free refund, especially on award bookings for a schedule change of 30-minutes and more, although some first would not but after not being able to offer the rebooking option, they gladly offered refund.