maybe she thinks you are gay and rich so therefore safe, hmmm orange cordials could be...... and i doubt she "bought" you guys drinks, i bet you her boss paid for it, i know a LOT of bartenders, and can tell you a lot of them run scams, nature of there business.

One other theory....she just wants to party her ass off everynight and needs posse, and really is not interested in you, so tells you she has a boyfriend.