This is something I have ran into recently and it deals with situations where the one night stand is forced. As in there is a low chance you will ever see her again so you basically have one day/night to close. ALWAYS get the number, even if you know for sure you will never see her again it's not an excuse. It's good texting game practice. I sometimes get numbers for the sole purpose of constructive criticism. If someone knows they will never see you again there is a good chance they will be honest with you and tell you what you did wrong/weird during that encounter.