As a
safety mechanism, I don't mind it. I'm sure it's useful to know when the
dump truck you're standing behind is about to roll its enormous wheels over your
tiny broken body. That's fine, I'm happy with that.
My gripe with the "backup beeper" is that it falls victim to the natural human phenomemon of desensitization. If you hear beeping frequently, or worse, at all times, your brain will naturally begin to ignore it--just as you don't actively notice that you're wearing shoes right now (if you are wearing shoes right now!), those exposed to the constant beeping relegate it to the background of their consciousness. Once that has happened, it loses all value as a safety device; it's designed to make you aware of the imminent movement of large objects, but by its very repetitiveness and ubiquitousness, it makes you less aware.