As for the light, sounds live they were just out revenueing. If you contest (bring your CFR's) I bet it gets thrown out. However, it probably would behoove you to get a set of those new aqua signal LED suction cup lights to avoid future interactions with the revenue man. But it is a viscous cycle. Next they will be out measuring the spacing of your registration numbers with a micrometer...
A sounds device is required. Get those cheap two pack whistles and tie one somewhere on every dingy you have. Be sure to demonstrate its use for the revenue man. They like that sort of thing.