I agree with Tam.. plus.. in this day & age, contracts are as good as the people who sign them.. Judges are more and more saying that people have the right to change their mind. Contract or not.. It's just one gal.. not as if she's wantin to take your entire site down..
There'll be plenty more to put in her place, and when her bf dumps her, or she dumps him and she's knocking on your door again to do another shoot cause she's broke.. Just smile and close the door..
