Back in the days before voice overs a friend bought one of those tilting alarms that you fitted behind the rear numberplate on your bike (I forget the name /make). It went on a Bonneville to begin with and then moved to his Trident. It was ok for a bit until a combination of weather and vibration took its toll and then it started going off at random - even when you were riding along. I seem to remember it finally got switched off permanently with a hammer. A voice version going off intermittently as you rode past the Co-op would probably not have had hoards of people seeking the address of their local Triumph dealer.
The only time I've ever known any voice response gadget actually work as intended was when I bought my first ansaphone. All my attempts to record a message ended up sounding like a speech therapy exercise so I got a French lady of my acquaintance to record the message. It was initially meant as a joke but the 'nuances' in her diction proved so popular it stayed for a few years until the tape wore out.