Really? You get snow build up on the hood while driving? I've never experienced that before.
No offense but...
I guess you never drive on highway 2 between Edmonton and Calgary in the winter with tractor trailers passing you in slush and wet snow,
or checking calves in the field at two AM in a heavy windless snow storm at 2MPH getting out of the vehicle every two minutes,(my part time occupation!)
or driving through five foot snow drifts on our dirt road with enough speed to penetrate them instead of getting stuck in the middle...
I could produce some pics if you doubt me...
More of an issue with the new lights running much cooler. I remember my CIBIE Super Oscars with heavy ice buildup forming a bridge to the bumper due to the heat generated by the units...
The problem I see is the backflow of air going under the light array and curling back forward depositing heavy moist snow back on the hood not necessarily a problem without the lights in place, icing could also create a problem but it's applicable to all lights on the vehicle.
Different application cause different problems but you are correct, under normal circumstances and use the snow should blow by.