I completely agree... playing games is only going to hurt her more. Trust me. When she figures out this is what has happened she is going to be so upset with you, which will then only lead to her trying harder not to tell you things, she will lose trust, and probably will retaliate in a way that is only going to hurt you both.
My mom use to do similar things .... she'd read my text messages to find out what i'd been up to, or my conversations on msn ... and then eventually, she used me seeing a T as a sort of blackmail to what i wanted to do with my life. I'm not saying you do any of those things, but that sort of mistrust only damaged our relationship ... and now, to be honest, my mom doesn't know much about my life. I doubt you'd want that same sort of relationship with your daughter...
I truly think that it's in both of your best interests to just be upfront and honest with her. Without honesty in a relationship .. there is no relationship.