This just popped in to the noodle the other day while doing my normal youtube binge.
In an effort to add some realism to a training scenario, what if a large mylar mirror was hauled out to a suitable distance (?) and used to reflect a scene so that you could have live targets safely engaging each other (crudely depicted here)
Hits would be a little challenging to detect, possibly using a video camera from the shooter's position or affixing a small laser to the shooter's firearm that either shines constantly or flashes when a shot is detected. The laser would of course follow the optical path and hit the target while the round sails through to whatever backstop is in place.
Mylar is relatively inexpensive and if held taught can make a pretty good reflective surface. A single sheet would take a lot of hits before it was unusable.
I like this vs. paintball or simunition because you could use full power rounds and wear nothing more than standard range PPE. Of course the target could shoot back and you'd have a pretty interesting scenario.
Here's a poor man's version using a small emergency blanket -
https://www.youtube.com/watch?v=FyCLOXF1188
Edit: it seems the trade name for this kind of thing is a 'glassless mirror'