So my sister and our boyfriends decided to get together to play Munchkin tonight, and we started to discuss how unfair my parents are to her. She's almost 20 and I'm 21, and I've been allowed to stay at boy's houses since I was 18 but my sister still isn't allowed to have her boyfriend over during the day when nobody is home and they freaked out when she said she was going to be going on a road t…