Dudes its not like he is running route irish at 50 mph around midnight. He is playing HIDE and SEEK with his friends on quads. He didnt ask an opinion wheather you think its safe. Like hitting a 40' double is safe. Its just a game usually pretty slow speed, it is dark ya know.
I still think you should go with the night vision goggles, there are cheaper models out. You could get some tinted plexiglass and put that in front of your head lights to get a dimmer light effect also.