tracking pilgrims using RFID

http://cdn.intechopen.com/pdfs/8496/InTech-A_case_study_of_an_rfid_based_system_for_pilgrims_identification_and_tracking.pdf   Here is the link for tracking pilgrims using rfid. Don't know if this is feasible as cost is high and defeats the purpose if no one wears the tag or want to be track.