I respect every opinions about hearing dog...
Let me tell you about myself bit.
I grew up with pets... It's not just dog but cat as well. I have many dogs and cats come and go in my life. They bark automaic when the door ringing... I can't see the sense why it's necassary to have hearing dog... They helped me... They barked first before hearing people... Don't you know that dogs and cats hear shape than human? Why educate dog to be hearing dog for... ?
I have 2 cats... They heard the door ring before me... I knew straight way someone come when I saw cats jump and stare the door, sometimes ran to door... They noticed that we can't hear their cries outside of door (that's time my sons are not home). What they do is jump on the window to get me attention then I open the door and let cats go in...
Okay, I respect your opinion but I think it's not necassary to have hearing dog...