If you have a subpoena to sniff data to Apple from device X then you can use that to some extent track the location of X by spreading your Tags T_1,...,T_n in i

If you have a subpoena to sniff data to Apple from device X then you can use that to some extent track the location of X by spreading your Tags T_1,...,T_n in interesting places. If X reports T_i you know the location of X, this could be more precise than the usual cell phone tracking because X reports its position with GPS precision.