Every night I can hear ubers reversing up the road with their obnoxiously loud lorry-style reversing warning beep. If I'm not already asleep, it keeps me up (and for some reason it takes them forever to park or whatever they're doing).
Obviously it's marginally more safe than not having a beep! So, you know, ancillary impacts be damned...
Tesco delivery trucks have them here in Ireland; it's pretty good stuff. Still quite loud/noticeable when you're up close, while at the same time not being completely obnoxious to everyone in a kilometre radius.
Looking at their website it mentions several patents, so perhaps that's one reason it's not more widely used.
Good lord, I've gone a long time without knowing what that was all about. First time I heard it I assumed the lorry had a broken reversing beep speaker or something!
Car alarms are similar. Maybe (but doubtfully) they'll prevent your car from being stolen/trashed/emptied. But at the cost of waking up an entire neighbourhood every time a bird shits on it a little too forcefully (or whatever it is that randomly sets off car alarms in the middle of the night). That's not a tradeoff that works for me.
Your house is on fire? Fine, wake up the whole neighbourhood. You're in physical danger? Sure, emergency services can be as noisy as they need to be. Some of your stuff is in danger of being stolen? Meh, I don't want to get out of bed for that.
Obviously it's marginally more safe than not having a beep! So, you know, ancillary impacts be damned...