After all passengers have disembarked, the CAS have to advise the ground staff the all passengers have disembarked . They have to check hatracks, stowage bins, and seat pockets for lost and found items and give them to the ground staff. They also have to recheck and toilet articles. During a transit stop, or normal ground stop. The CAs have to supervise the cleaning of the cabin interior, galleys and toilets. The cabin crew remaining on board must ensure that safety instruction, in particular the smoking rule, are obeyed. During short ground stop, many procedures apply. Transit passengers must remain on board. An appropriate announcement has to be made. The "no smoking". Smoking is strictly forbidden. This is to be monitored by the cabin attendants. Crew members whit no specific duties on the ground must remain on board. If refuelling is taking place, CAs must be vigilant for any sign of fuel vapour escaping into the cabin. Airlines, airports, and security authorities in a particular country enforce different policies on whether passengers may stay on the aircraft on routes which do not involve a change of aircraft. For example, flights that require stopover merely for refuelling usually do not permit passengers to disembark from the aircraft. On the other hand, flights where there is a change of passengers may require that passengers disembark and stay at a holding area for security reasons and a proper headcount. In relation to this, a direct flight with stopovers may or may not involve a change in the flight crew.