Given that VFR implies the ability to orient the aircraft's attitude and height by means of visual references, it's really not possible to call any night flying VFR unless you're over a well lit area (like a city).
True. The thing is, with our rules, you can fly night VFR without a visual horizon as long as you're in VMC (eg clear of cloud with the required visibility), use appropriate safety heights and can navigate with reference to ground lighting or features, using attitude indicator or AH for attitude info.
The implication is that you can fly on a no moon night with no discernable horizon, and therefore not even know you're about to go into cloud if it's dark enough!
The potential for stuff-ups is high to say the least. There aren't any mandatory instrument flying recency requirements for NVFR.
I trained in the military before goggles were commonly available, and consequently was used to dark night departures, transits and approaches to fairly basic light sources, so I know it can be done safely with the right planning and training. However, we had a strong IFR background too, which I always considered to be the ace up my sleeve if everything went pear shaped, something that many of our civilian counterparts don't have.
I'm not commenting on any of these accidents in particular, just pointing out that after relatively little training, you can legally go and do some extremely demanding flying at night in this country. By all means, have the capability, but we need to back it up with appropriately rigorous training, and I'd personally like to see all night pilots instrument rated.