I have noticed that for a given flight, there are two checks of the passport and visa documents, once at the check-in counter and then at the boarding gate. Why is such procedure being followed?
I noticed that airlines, twice, do check the details of the visa (validity, number of entries, if used already, etc.). In fact, I am aware of cases where a passenger has been accepted at the check-in counter but rejected at the boarding gate!
Why does this happen?
There are several reasons for this:
Not all passengers use the check-in counter. Nowadays with airlines charging more money to check-in luggage, more passengers just carry hand luggage. This means they don't pass the check-in counter but go straight to security. Therefore a check at the gate is necessary.
As mentioned in the comments:
Also, the boarding check is a bottleneck. If at all possible, the airline would rather catch problems at check-in.
This is also true. If the passenger is caught at check-in, this will cause less disruption for the airline and other passengers later on.
If a passenger is refused to board, his luggage has to be removed and the flight can be delayed by a considerable amount of time.
Delayed flights costs the airline billions each year. The airline doesn't want extra costs. First of all, not everyone uses the check-in counter. Some only carry hand luggage and proceed straight to security and to the boarding gate.
Checks are also done twice to make sure there are no mistakes, as a mistake can cause the airline a lot of problems. Some people could also have been missed at the check-in counter. It’s like asking why do airline staff check your boarding pass at the gate and on the plane, to make sure you’re not on the wrong flight!
This could be because checks weren't done properly or at the gate something came up on the airlines system.
