Leaving outside camper lights on?

Left my porch light on all night by accident once... went to the bathroom around 3am and noticed camper next door had light on, must be early riser, no worries. Woke at up a 5am and went to put coffee on and realized that the light I saw next door at 3am was the reflection of my porch light. Dad said he knew I left it on by accident and he just closed the blind to sleep. I went over around 6am and had coffee with him..