Ferrous Oxide
I run an event that fills up pretty quickly once we announce that guest doors are open. We open the the instance as a group instance with instance queue enabled. After we get all of the staff into the world for the event, we announce on discord and in group pings that the instance is now open for guests to join.
Guests should be joining and starting up a queue at the announced time. What they can currently do is use the "Show Go Button on Load" setting to preload the world and reserve their spot in the instance. We can't tell what guests are doing this because they don't load into the world, we have no idea who hass connected early. They simply join the world with everyone else once the ping has gone out.
You can test this easily with 2 other people.
1) Create a group instance with a queue for a world with 2 max slots. Just the two of us works well.
2) Have the instance owner join first and load into the world.
3) Have the person who will use the "Show Go Button on Load" join the instance, but not press the join world button.
At this point, the person inside the instance does not see anyone else in the world. The person in the load screen has reserved their spot in the world.
4) Have a third person attempt to join the instance. They will either be placed in queue, or receive an error related to needing to join a queue but it will not place them in a queue.
From the perspective of the person inside the instance, no one has joined. The third person cannot join the instance and MAY be able to queue. The second person that is waiting to join can join freely at any time.
I do not know how long this instance slot reservation lasts, but it is causing significant issues with group instances with queues.