I just sent her a text and said "MAKE SURE YOU COME ALONE"... gotcha!!!
If by any chance your "gotcha" is directed to her and not us...
First of all, if she comes with friends, she'll tell you she never got the message.
Secondly, this makes you sound like a creepy control freak psycho. Maybe you are! Trying to control the outcome (by controlling the people) is what you're doing here.
Thirdly, by trying to run her play, you're not permitting her to show you her cards. You have to sit back and let things play out. What if she was going to have her friends run interference but now decides not to? That doesn't mean she'll be more into you than before, it just means now she knows she needs to up her game, but now you wouldn't know if it's that or not.
You can't let on that you know what her game may be. You have to see if she'd play it or not. Then, be prepared to volley back.
What if she WASN'T going to bring her friends? Now you'll never know for sure. You just HAD to interfere and contaminate the playing field. You have no self-control. I wouldn't be surprised if she doesn't show up.
Rather than dictating to others how you want them to be, it's better to be hands off, and if it turns out that they pull crap or they raise flags - GREAT!!! You can next them and move on to something hopefully better rather than waste more time like you did with little Ms. Drama Queen Co-Worker.