hi nightshift,
a key part of "location sharing" is privacy. that is, consent MUST be
collected from the end user before location can be accessed. this is
inline with MMA and CTIA best practices.
as part of consent, the prudent approach is to verify that the end
user giving consent has physical access to the phone being located.
that way, you can't type in my phone number and give consent to locate
my phone (unless you have access to it). of course, this is why
ongoing notification to the phone in question is also required... so
that if you swipe my phone and return it with the hopes of locating me
without my knowledge, I get notified.
can you help us understand what use case you're trying to support? or
what kind of customer you're targeting that is unlikely to have SMS?
thanks,
jason