5. She Keeps Mentioning That Her Roommate Is Out of Town

This could help tip you off before the date even starts:

You: "So, you wanna see The Smurfs or Conan the Barbarian?"

Her: "Did I mention my roommate left for Greenland this morning?"

Pretty clear that she's trying to tell you a couple things: 1. There's no need for the hat on the door trick at her place tonight. 2. Her roommate is some kinda uptight environmentalist type, and now that Debbie Downer's off saving seals, it's your turn to score some pelt.