"If you have ever felt uneasy about an overnight activity, don’t be afraid to respond to that warning voice inside."

The mere fact that he mentions feeling uneasy about an overnight activity also means that there may be other overnight activities that you don't feel uneasy about. He's not advocating never allowing sleepovers. He's advocating making an informed choice about which overnight activities to allow.

This may be an unpopular opinion with some, but too many people think that not allowing their kids to go on sleepovers is good parenting, when in reality it's lazy parenting. You need to take the time to get to know your kids' friends and their parents. Find out what kind of supervision there would be. Find out what activities are planned. Find out sleeping arrangements, bedtime plans, etc. Then make an informed choice while listening to the spirit, just as Elder Lawrence suggests.