One trainer (Louis Awerbuck) I know uses this approach with students. It's a challenge... every time.
http://www.yfainc.com/mirage.html
In 1989, YFA originated the Mirage Target System to try and address the problem of training on flat, stationary targets on the range and then facing 3-dimensional moving targets in the streets. Another purpose of designing this target was to make the shooter understand that he is responsible for the terminal resting place of projectiles and to concentrate on shot placement so as to be able to better judge whether an intended shot would be viable.
Originally, the system used flat or curved cardboard with targets that simulated a human form. It then evolved into a system which utilized 3-dimensional plastic humanoid-shaped targets on which clothing was draped in order to present a more realistic figure. We added the availability for the targets to simulate holding a hostage in front of them, and then the availability to have more than one target so as to better simulate a bystander problem.
Today, the system takes up to 6 humanoid targets, any one of - or up to four of - which can be set to move erratically. The configuration in the accompanying photographs show the middle target sliding between two others. This particular setup forces the student to take angles of fire and foreground and background problems into account. The target system is utilized in all YFA courses so that the student can put together many facets of the training he has received in a situation that is as close to a street problem as possible for range training.
Over a dozen years ago, YFA also pioneered the use of three-dimensional and negative paper and cardboard targets to "acclimatize" the trainee to the concept of defense against human adversary-shaped forms and finite shot placement.