Let me vent about this for a moment

First off my best friends little sister called me today and asked me if she could talk to me since I know a lot about woman stuff. I told her go on? Listen to this: she took a pregnancy test and it was negative. She hid it in her room for safe keeping. She told me her boobs were still hurting her and no period so she decided to retake the SAME pregnancy test and it came out with a faint line. I asked her before she retook the same test if there was a faint line and she said no just the regular line. So she basically called me to ask if it's valid? I told her buy another one since hpt are only meant to be used once... I'm just blown away at the fact that a test could get a line after being reused and that she actually reused it.