People... watch out for these things!
The saying applies with more than usual force here: if you're not paying for it, you're not the customer: you're the product being sold. (And maybe you're the product being sold even if you are paying for it.)
DO NOT MAKE YOUR PERSONAL PHYSICAL DATA AVAILABLE TO PEOPLE WHO COULD THEN SELL IT TO THOSE INVESTED IN USING IT TO SURVEIL YOU AND POTENTIALLY CHARGE YOU WITH CRIMES.
The most recent generation of Internet users has been carefully and systematically encouraged by Big Data to get casual and easygoing about (for convenience's sake) trusting their data in the hands of total strangers. Time to break that habit.
Don't make it easy for yourself to become someone else's horror story. Take a careful look at all the apps you've been using and taking for granted, and start asking questions about who gets to see the data you give them, and just what they get to do with it.
Warning!