OK all you killjoys that are talking about security cameras and such cut it out! Abigail is asking about fantasy, make believe, "what if" kind of stuff. Not reality.
I do go into stores shopping en femme and en drab and the bummer always is my desire overcomes my budget.
Here is what I would do. I would take every mannequin in the store and arrange them like they are watching a fashion show. I would also pick out every outfit I have any interest in wearing and I would be the one wearing it down the runway! After that I would probably call my buddies the lock smith and the computer hacker dude from the Oceans movies (Fantasy remember) and have them bring a U Haul and help me move all of the outfits I like out of the store. I would make sure computer hacker dude erases all of the video footage of the heist.
Wait! This fantasy is too self centered. I need to be philanthropic. I would take the Uhaul and deliver all of the fashions to the shelter for underdressed wayword transgendered women.