Devil is also in the details of airline luggage rules
Always check the fine print. That advice also applies to airlines' rules on luggage, the Consumer Council said as it revealed that complaints in this area doubled last year - from 14 to 30.
In some cases items disappeared or were damaged; in others their delivery was delayed or came with questionable additional charges.
Timing is crucial for claiming compensation, as demonstrated by one woman's complaint. Her luggage was missing after she returned to Hong Kong from France. She contacted the airline and it arrived a few days later.
After another 10 days, she sought compensation from the airline on discovering that some items in the luggage were missing. The carrier rejected her request because she failed to provide receipts for the lost items.
The airline told the council that the woman made the report too late. People can only claim compensation for baggage within seven days of taking the items from the airport, according to the Montreal Convention adopted by members of the International Civil Aviation Organisation. The convention provides a liability system for delays, loss, damage or injury to baggage or passengers.
Passengers should also pay attention to the weight limit on bags, especially when transfers are involved, as shown by another case.
A mother bought two tickets to Manchester on an airline's website, and was told her daughter, a student, could take 35kg of luggage.
She was dismayed to find out this only applied to the flight from Hong Kong to London; the cap for the connecting flight to Manchester was 20kg. The woman had to pay for the excess.
The airline refused to compensate her for the additional charges. It said the connecting flight was operated by another airline, which did not recognise its student-baggage discounts.
The council also advises passengers to check what valuable items are prohibited in checked luggage.