I don't care I'll still use the free wifi. These stores are going to have problems, and it's just not the privacy aspect. They're going to have problems with the tracking accuracy. I don't know about everyone else, but I sometimes go to stores just to use the wifi. You'll see me aimlessly wandering through the store trying to look interested in buying things. They're going to have a hard time because of people like myself.
To get accurate data, they'll have to connect both the wifi data and the security camera data to weed out customers that are just using the wifi. I agree that they've been doing this for a while. Both with the security cameras, and with the club cards or store charge cards. It's not new, but physically tracking someone can feel make one feel stalked.