We have a 13YO Rotten Shepherd, more Rottweiler than GS. A couple of years ago, we left our front door wide open on Christmas Day. Definitely a miscommunication between my wife and me.
I drove back to the house after a couple of hours, and the dog was perched in the doorway. I suppose she'd been there the whole time, protecting the house.
She's a great dog, friendly and good with kids. We're delaying the inevitable, her arthritis is catching up and she needs a shot every 4-6 weeks.
Sigh. We do love our animals. They brighten our lives.