As I said above, I have probably fired at least 100 of these flares. The requirement was to fire them above 1000 ft agl as by the time they reached the ground, they were burnt out. An auto from 1000 ft would probably take about 45 secs during which time the surface was well lit. A Nite Sun is not really a 'sun', more an oversized torch ( flashlight for Sasless !) and does not compare with a flare for surface lighting.
I have no doubt if fired too low, they could well cause a fire but being in the Navy, most of my flights were over water. A Very pistol is far more likely to cause a fire. Also I never had a flare malfunction.
How many of you have done a night auto onto the sea? I have done 1 in a 206 on floats with just the normal landing lights about 1/2 mile offshore with a full moon, no rad alt and I can assure you it was quite frightening.
I agree flares seem to be out of favour but that doesn't mean they weren't worth while.
