Suzuki S Presso has no alarm system

After having a break-in to our Suzuki S Presso and theft of the spare wheel it became apparent that this vehicle is sold without an audible alarm system. In crime ridden South Africa I would have thought it would be standard to have an alarm on a vehicle, but not is some Suzuki vehicles it appears. I was then advised by a Suzuki dealership that if I fit one it will void the warranty. The Suzuki dealer does not offer an alarm as an extra.