To be blind in the true sense

I guess we all get confused sometimes...but this seems to be a reasonable shocker...

Friend #1 was walking with friends, 2 and 3, who didn't know eachother. Friend 2 happened to be deaf.

When stopping at the lights, the "beep beep beep" sounded to let those that are blind know they can cross the road, when friend #3 said to #2 "Does that really help?"...

I guess to a person who hasn't put a lot of thought into this, maybe all disabilities appear the same...