There are those that have flown in the dark.....then there's those that have flown at night. Seems some that have never flown with NVG's have done both.
Once you fly with NVG's.....the thought of flying in the dark will scare the bejeeus out of you. Having 20/40 vision with a limited field of view beats hell out of being blind.
Yes...there is an element of risk that one might find yourself in cloud but generally you can see the cloud first. Fog might catch you....but then it will catch you without the NVG's as well.
The safety improvement with NVG's far surpasses any new risks they might present. The very same weather analysis needed for NVG flight is the same for any other flight.
Has there been an accident involving an EMS aircraft while the pilot was using NVG's? I have not heard of one.....has anyone else?