B-Donor is different .. Your data will not be available to requesters but you who will receive notification on your mobile for requests of compatible blood group near to your saved location. Requester will not know any donor's data. You also may go to hospital and donate without a phone call. The app use your location only once during sign up then send notification based on location you selected on the map. After sign up you can revoke GPS access.
Privacy statement for B-donor application