I built a device similar to this (with a raspberry pi). iOS from 7 and up no longer allows getting mac addresses... so it's much harder to tie a mac addresses t

I built a device similar to this (with a raspberry pi). iOS from 7 and up no longer allows getting mac addresses... so it's much harder to tie a mac addresses to actual purchases. You'd have to do some sort of collaborative filtering over tons of visits to reliably tie purchases to a mac address.