So outdoor advertisers can potentially pixel customers who see an "impression" like they do for online ads and track conversion behavior if they ultimately walk into a store?

The article doesn't speak much to this, but what opt-in permission would a user give to actually allow their location to constantly be relayed to advertisers to make this possible? Would Target need to hide this in their T&C of their app and then match it against the billboard's data on an advertiser-by-advertiser basis...?