On a dark beach at night, white would be the color that stands out, and be remembered by witnesses. So, the fishermen may be remembering the white top of the Suzuki.
On a dark beach at night could silver/gray appear to be white?
That makes sense... PvdS's Suzuki Samurai would appear mostly white when viewed from behind or above the vehicle. For example, if the vehicle were backed down a beach incline, the white roof top and white side canopies would dominate the view... a passerby would reasonably perceive "white" as the color.