Only the people you choose can get information from your phone. Unknown persons cannot reach any information remotely. Also you can start and stop application with just one click.
HOW DOES SMS REMOTE WORKS?
The remote user can send you two different basic SMS message.
When remote user sends you an SMS message only contains "location" word, your phone determine your location and will send it back to the remote user.
2) vcard name_of_the_person
When remote user sends you "vcard michael jackson", your phone checks your contacts and if there is a person that remote user is asking for, SMS REMOTE send an SMS contains that persons phone number information.