There are already such apps in South Africa, so it is worth comparing monthly costs, coverage areas, and how they are triggered, e.g. some will also trigger from an Apple Watch by long pressing a watch complication. This one starts at R35pm but remember you get what you pay for, so be careful of 'free'.
See New personal safety app sends help instantly, you just need to shake your phone
Refilwe Moloto speaks to Michael Brown, executive director of the new 'bodyguard-on-demand' phone appilcation iFearLess.