I've accidently locked Pearl in my closet a few times before. She usually started meowing so it doesn't take long for me to rescue her.

When my RB Pepper was a kitten he door dashed as I was bringing in my laundry. I didn't notice that he had done this. My front door opens up to a hallway. A little while later I heard a loud meowing but I couldn't find Pepper. I finally opened up the front door and there he was. At least he was smart enough to know which door was his home and to meow to alert me.

Sky's also been locked in my roommates closet and bedroom before. He loves to visit and he usually doesn't meow or complain so I have to go looking for him.