We found they check in easy but had delays as other passengers hadn't checked their luggage allowance. Our allowance was for 6kg hand luggage as per the booking info.
A large number of passengers checked in ok but they had problems at the gate as they had more than their allowance and the bags were weighed before boarding. Some passengers had to pay for hold luggage, some chose to put on lots of clothes!
This lead to delays at the gate and as you can imagine wasn't the start to the holidays that everyone wanted.