We've had this issue too. Light out time is lights out time. Saying that, my pg ds7.5 woke up wet one time at 2 am and then started to read Stephen Hawking's book, George and the Secret Key to the Universe. My husband and I had to laugh; we both have library degrees and wanted to foster reading, but not at 2 am!
We've managed to somewhat get around this issue by giving ds a quarter of a melatonin pill about an hour or so before ds goes to bed. This way, he can read but usually conks out within 30-45 mins. Everyone is happy then. Ds gets to read before going to sleep and ds actually goes to sleep! Daddy and I get some peace and sleep too.
I would never punish a child for reading since I have a library degree. Instead, I emphasis the point about the need for the brain and body to sleep with eyes closed.
You can't really force a child to sleep, but you can set the right conditions and environment. I'm guessing adhering to a bedtime here is the issue rather than reading for pleasure. So if this is case, I would work on improving the conditions and environment for sleep - ie. Epsom salt baths before bed.
