SUBREDDIT: r/AskReddit
TITLE: Help me teach my roommate a lesson - lock the front door.
POST: I live an apartment with about 30 units or so. My roommate just moved in, and she NEVER locks the front door. I have about $3000 worth of stuff in the living room including my laptop, HDTV, HTPC,
TL;DR: 
Roommate doesn't lock door to apartment, need to teach her a lesson/pull a prank so that she will lock the front door.