I've often wondered, but never thought to ask:

Why is the tell echo different for the Vale of Shadows but not anywhere else in Thera? (to my knowledge at least)

Too often when I travel there I get asked to turn DEAF on so that people sending me tells won't know where I am. In a sense it is self defeating, but the simple fact that it has that ability seems just silly.

So why is the echo different there and no where else? And is there any possibility to have it changed?

There are a few others places to make that happen. One of which I would highly recommend using to trick people into thinking that you are in Organia, only so that you can follow them in and kill them.

Enemies: Stop sending random tells just to see if someone is in Organia. FFS.