Some operators love to turn their machinery into Christmas trees, festooning tractors, combines and pickups with extra lights in the hope of easier night work. Or maybe (whisper it) just to impress their mates. Either way the result is not guaranteed to be effective, either in cost or in better vision. Although there may be plenty more lumens about, these may not land in the right place: get things wrong and bounced light can end up dazzling the user or operators working in the same field, while lamp control circuitry can generate electrical noise and interfere with the radio. And that would not be good.