I know slightly different scenario but i have booked Cosmos BHX-Skiathos and it wasn't until the final screen that it said your flight home stops at Kavala. Not quite the same as that is a definite stop and this instance BHX-KVA is also bookable but I would imagine would put a few off.
Pete
Fuel stops for Skiathos outbound flights have been the norm for many years depending on the equipment and loads due to the short runway there.