It may depend on what you mean by personal items. I would not leave expensive jewlery or cash in my bedroom.
When I travel and I leave my room, I close the door and the curtain and do not leave any electronics out where they would be visible. I always take my cell phone and purse with me when I leave my room and I do not wear expensive jewlery.
If your door is shut and the curtains closed, a would be their has no way to tell if the room is occupied. I usually just keep camera/scanner laptop in a closed bag out of the way and don’t worry too much.
I agree with the previous responses. I try to close the curtain and the door when I leave the room and keep things of value out of sight. We have never had a problem. Sometimes closing the door doesn't always work because doors often slide open and do not stay closed
The only problem I ever had was when I was a coach passenger in 1972 on an overnight trip on the Floridian. Before I went to the lounge car in the evening I placed my camera bag on my seat and to hide it I placed my Woolwich jacket over it. When I returned the jacket was gone but the camera bag and contents were fine. I figured the person who took the jacket must have needed it far more than I did.