I would hazard a guess that his bikes headlamps are wired to always be on when the bike is on.
In Cambodia it is illegal to run lamps in Daylight and gives the police a reason to attempt to stop you and extort a bribe of between $1 and $50.
Mind you, they don't try too hard when a bike is bigger than 250cc as they would get knocked on their asses/ dislocate a shoulder trying to grab the rider.
In general, if a policeman steps into the road waving for you to stop, the correct etiquette is to gear down and wind the throttle up and drive directly at them.
They will get out of the way