For me it was a real eye-opener how much footage from even relatively simple scenes was shot on a green screen, with a background composited in afterwards.
The advantages from the production perspective are obvious - you don't need to travel, get location permits and are not dependent on the weather. And creatively you are limited only by your imagination.
So what has this got to do with travel photography? Compositing in still photography has been around for a long time, and has become extremely prevalent in the last 10 years as Photoshop has become ubiquitous.
However, it's only been relatively recently that it had been common to see travel posters on the tube here in London where a couple or family have been composited onto a beautiful background. Sometimes it is done very sloppily and looks terrible, but often it is done with great skill and would not be noticeable to the casual viewer.
I can imagine this is a trend that will only accelerate in future. With high quality stock photography available for backgrounds, models can be shot in the studio without the need to expensive travel and weather delays.
The green screen is here to stay.