Yes, I've often considered what it must be like for the taxi drivers these days with the advent of uber, Lyft, etc.. doesn't make it right to attack others! I am so sorry to hear about your friend that's absolutely horrific. I have mace and another legal weapon easily accessible but out of sight in the event i ever have a hostile passenger. Uber does have safety features and "alarm" buttons that can instantly alert authorities to my area, but even so by then the worse could've already occurred. However with mass shootings becoming a sad "norm" and simply stepping out your front door leaves a lot up to chance, anything is possible and it's no different in this industry, sadly.