Imagine, if you will, a desert plain, covered with sand for as far as the eye can see and beyond. During the day, the sun is scorching hot, and the wind blows the sand around. There is no source of water in sight, no source of refuge. At dusk, temperatures drop quickly, and within a few hours it becomes cold enough that you could see your breath, in the moonlight. The winds continue, chilling you to the bone as you trek across the sand, not really going anywhere, just going. It doesn't much matter, as there's really no place to go - it's all the same.
Now imagine, in the middle of this, a huge dome. The dome is constructed of a translucent but impenetrable material; if you're close enough to it you can sort of see inside, and anyone near the wall on the inside can see out. There is only one entrance to the dome, blocked by a door that can only be opened by the guards within. Inside, there is heat and air conditioning, plenty of food, water, all the amenities of home and more. If you put your ear to the wall of the dome, you can barely hear music and commotion inside; there seems to be a party going on. You can try banging on the wall, but it does no good; the sturdy wall absorbs the impact and the sound is muffled quite effectively.
Every half hour to an hour or so, some kind of transport vehicle arrives. Being a Star Trek fan, I'm thinking of something like a large Federation shuttlecraft, which touches down just outside the door to this dome. About 20 or so passengers disembark, accompanied by a few polite, friendly but well-armed guards. The group lines up single-file, and one by one, they approach a podium set up just inside the door. Behind the podium stands a man with a list of names, and another guard. The first person approaches and gives his name, and the man behind the podium looks through his list. Upon finding the reservation, the man behind the podium welcomes this first guest, hands him an orientation packet, and points him down a hallway leading somewhere inside.
A woman approaches, and gives her name. The man behind the podium glances at his list, finds her quickly, marks a check by her name, hands her a similar packet and gestures down the hallway.
Another man approaches and gives his name. The man behind the podium looks through his list, stops, and looks over it again. “What was your name again?” He checks again, just to make sure, but this man's name is simply not to be found. “Im sorry,” he says, and a guard approaches. The man is quickly escorted away from the entrance, sent off into the desert to wander.
A mother and her small boy approach the podium, holding hands. The woman gives both their names, and once again the man looks through the book. Finding the child's name first, he hands him a smaller packet with a coloring book and a small box of crayons. However, the mother's name is not to be found. The man shakes his head and again says “I'm sorry.” The woman, slightly hysterical and clutching her son tightly, insists that there must be some mistake, but (after double-checking once more) the man repeats that although her son is welcome, she is not to be allowed inside. A pair of guards come forward to separate the two, and tears well up in the child's eyes as he realizes what is happening.
The woman is dragged away, crying helplessly for her son, who is hesitantly taking a few steps inside. Upon being released by the guards, she runs back to the wall of the dome and presses her face against it, sobbing. The boy, inside, runs to her, touches his hand to the wall and yells “Mommy!” The two share a moment of tears, and then he turns away, leaving her alone outside, and begins walking away. He stops, turns around, and watches her for a moment, still pressed against the outside of the wall with her hands over her eyes to shield the bright sun. After another moment, he turns away again, and she knows he is gone.
The next man in line, clearly shaken by what he has just seen, gives his name, and is again welcomed. A few more are turned away, and a few welcomed in; the transport then departs to collect another group.