Sorry if this "bumps" the topic and is against the rules. Also, if there's an obvious answer. I'm new to all this. I was reading through the guidelines and rules and came across one which seemed interesting and confusing.

"Don't keep your lights on when parked-up. If you're afraid of the dark, stay at home." 

This one was in the single guys section. It's interesting because I was out one night and being very patient, was there for three hours. There was a guy who came in and was waiting around and for the entire time, he had his headlights on. All I kept thinking was "you're going to have a flat batt by the end of the night, mate!" 

To get to the point, can anyone explain why they might've had their headlights on all that time or why it's against dogging etiquette? He wasn't shining them on anyone or anything.