"Queen includer" is a term used when a queen excluder is placed in a hive to confine a queen to a particular part of that hive. Probably the greatest use is to place it between the floorboard and the brood box when a swarm is put into a hive to prevent it from absconding, as they will often do, especially if hived on foundation. Once they have decided they will stay there are usually no problems.
A fertile queen in a swarm will usually start laying within 24 hours, so once you see eggs you can remove the queen excluder and you should be O.K. The problems arise when there is a virgin queen in the swarm, as they need to get out to get mated. In general a swarm will issue within a few hours of a virgin queen emerging. They take 5 days to sexually mature, so that is a maximum time the queen excluder should be in place. I only use this system where there is a virgin queen in a swarm, because I clip fertile queens when running them in. I leave the queen excluder there for a maximum of 3 days, less if they are building foundation out well. I know the difference between a fertile and virgin queen, but an inexperienced beekeeper may not, so it may be safer to use a queen excluder than clip her.
It is often suggested a queen includer can be used permanently to prevent a colony from swarming. It may for a time, but a lot of damage can be done to a colony in the meantime, including:-
There are several reasons why a queen may be imprisoned in one part of the hive, but this will usually be under controlled conditions and for a short period.