Just think, if all the cars out there were as quiet, there would be less background noise to mask the hybrids. I mean, we're pretty quiet (I snuck up on someone walking in the parking lot at work once, hehe), but not exactly silent by any means. Tires still grate against sand/pavement, etc. And aren't blind people supposed to develop more sensitive hearing as they compensate for the loss of vision?

Idunno, somehow I don't think the solution really ought to be "make quiet cars artificially louder".