Growing up as a kid this happened a lot. Mom would gladly welcome people in overnight - even strangers my father brought home from the university or church. There were times I would wake up and wander out of my room to discover someone sleeping on the couch. Often it was my older cousin who would just let himself in during the night. This really scared me as a child and teenager for what did my parents know of these people? And, if it turned out they were going to stay more than the one night, it was my bedroom they were given forcing me to sleep in my stinky brother's room (completely inappropriate as a teenager). There was one time I came down for breakfast to discover two scruffy and very frightening looking motorcyclists at the table. Apparently my mother had run into them at the convenience store the night before and felt bad about them setting up a tent in the pouring rain. For all I knew they could have been HA enforcers or other 'one percenters'.

So now that I am an adult with my own home I have made it absolutely clear that unless you have previously asked and I have agreed, one is not welcome to spend the night in my home. Show up for coffee yes, but anything more I require forehand knowledge about.