I think that's a great idea. A pedestrian horn. As you probably know, at least in the US, there are people who strongly advocate that EVs and hybrids should be mandated to include a noise maker of some sort when traveling at low speeds. Most EV advocates are strongly against that because much of the appeal of EVs is the distinct lack of noise and the environmental benefits thereof. But I tend to agree with you, I'd love the option of some sort of subtle pedestrian horn that I could use as needed. Sometimes, particularly in parking garages, pedestrians will be walking, maybe distracted by a phone and I follow behind them for quite a ways before they notice me (usually being startled by the fact that I'm there). However, I'm not aware of any sort of aftermarket product that meets that specific purpose. It would be nice if it were an OEM feature.