It's an APP that has been on your phone at one point. An APP by a company that is peak (maybe valley would be better) SV when it comes to ethical standards. Uber probably has a fingerprinting system that is on par to Google/Facebook and maybe even puts them to shame (maybe paints them in a better light).

I imagine that they wouldn't really have much difficulty tracking you through ad tech, another APP, or some other Cult Of Free system that is willing to sell database access.