helicopters should never be flown in poor visibility (night) I don't think the military recommends it.
Not sure if you're being sarcastic or not. (we really need a sarcasm font) but military aviation is really good at analyzing risk/benefit and we flew in some pretty dreadful conditions when we had to. It's hard to see that a flight to a charity ball game is mission critical though. It will be a high profile NTSB investigation and those guys do a very good job in breaking it all down. Who, what, where and why to the extent that they can.
I flew most of my operational career at altitudes from 200'AGL (day) to 400 (night) at similar speeds (maneuver flaps) and tight, fast turns chasing subs and mostly at night with nary a horizon or moonlight. The helos worked lower. Over land, about 200' and 400 kts, but ALWAYS VFR. Then again that was operationally required and not because going to a ball game. The old adage still holds for me; "I'd much rather be down here wishing I was up there, than up there wishing I was down here."
