I can see this as a safety disadvantage but at the same time, it has something to do with the equal opportunity act that prevents Uber from discriminating against the disabled, religion, veteran status, sexual orientation, etc.
I don't remember getting many cancels, I turned it on one day when I was messing with my settings and forgot that I did it. A week or so later I was talking with a pax and he asked me about it because it said I was deaf.
Took me a minute or so to remember it lol but I just played it off like I didn't know. I turned it off after and then thought back to all my other pax.
Not all of them will know, only the ones who haven't entered a destination and most pax do these days it seems.
I wouldn't count on it for high cancel rates, better to hide in a group of cars