There is a queue, they have just limited the amount of people who can queue. Basically rather than have 300+ people at a time queuing up to get into the server they have limited it to only 40-50. If there is no space in the queue you will get the wonderful server is full message.

The small queue is pretty quick and sometimes you will load in straight away as you wont notice its there.

This is meant to reduce the load on the log in server as to not have *rough guess* 16000 people trying to log into the servers during peak times (54 servers full queue of around 300) instead it drops it down to about 2500-3000 people.