00 Camry Headlight Question

While boarding a ferry boat at night I found that I was unable to turn off my head lights. The signs while boarding say please turn off headlights. This seams very odd. what if you are sitting at a drive in movie and it gets cold, you want to turn on the car for the heater but not annoy the people in front of you with the headlights. The only thing the owners manual says is that the headlights automatically turn to full intensity in the twilight even with the light switch in the "off " position. Is there any way to turn them off at night with the engine still running. Thanks Robert