European airlines are required to accommodate passengers in the event of weather disruptions. If your flight out of Hong Kong is cancelled due to a typhoon, British Airways have to look after you whereas Cathay don't.
It will be interesting to see the responses from the airlines involved. KLM operate on the SIN - DPS leg and could be up for a few hotel bills. This flight has about six codeshares on it but I reckon only those who booked on KLM or Air France would be in the running.
Obviously with the low costs, expect only a refund or rebooking.