ULPT Request: How to deter my siblings from sleeping in my room when I’m out of town.

My job has me traveling to different areas for about a week straight and my mom will allow guests and my siblings to sleep in my room. I don’t want this to happen anymore as I’ve been noticing items missing from my room. My mom won’t stop people from using my room so I need to take preventative measures from people using it. Moving out is not an option at this time.