Here's the gist of our policy towards screen shots:
1- If it is taken within a Yankee Air Pirate mission, it is encouraged.
2- If it is taken of our property outside of a YAP mission, you need our written permission to show it. This includes creating your own missions and posting them.
3- We do not allow public display of any modifications of our property without written permission.
Why? The hardball answer is to challenge you to show Mickey Mouse in a Nazi uniform and guess who your next call will be from.
The real answer is twofold: Our stories are real stories and many of the men whose stories we tell are alive. And many of them are referred to YAP things in the course of our communications. They are our only source of our only product. Once about two years ago, an enthusiast posted pictures that were okay for fantasy products but embarrassing as hell to the people in the story. For the sake of our promises to them, we protect their wishes.
And: The people who have created our objects are artists and craftsmen and although YAP owns most of those items, they would be insulted if they saw their work portrayed in ways that YAP did not intend. Every one of the people that have contributed to YAP (model, paint, INI, terrain, effect, or story) did so because they believe in the product. Without them, we would have no ability to tell our stories. So we protect their wishes, too.
Want to show a Day-Glo SR-71 nuking Ulan Batur? Have at it. Just don't use any part of YAP. There are plenty of other resources. But using our stuff to create a competing product, sell calendars, shoot videos or any other commercial enterprise must be done with our written permission. That anyone can understand.