What is wrong with people handling garden hoses?

I found myself having to replace the hose coupling several times a month. I
have an exterior spigot and I usually have a brass "Y" coupler connected to
it. One one side of the "Y" I leave it open the other side I connected a
garden hose to it. So every once in a while I had someone come by to either
do pest control, or repair stuff, or pressure wash something, or maintain
the pool etc...they need to use water. Pretty much every time they will end
up breaking my hose coupling. Either they strip the threads or cause it to
leak. I think they don't turn and unscrew the coupling from the spigot, they
just try to yank it off with brute force. So I have to cut the hose and put
in a new coupling. Sometimes they even use my garden hose and have to attach
their own fitting on the other end and that usually result in breaking the
couplings on both ends.

I don't understand why they kept breaking it.

Now this time I had someone pressure washed a driveway. After he is done I
know the hose coupler has to be replaced, cause when I turn the water on it
shoots out to the side again in all directions, it's practically impossible
to turn the water on or off without getting soaked.

Except this time the problem was not the plastic coupler on the hose, I
replaced that already and it is still leaking. Here is an image:

http://img.villagephotos.com/p/2005-...6/P1000492.JPG

I have indicated in blue lines where the water is jetting out when I turn on
the spigot. It is not the black coupler attached to the hose. It is the
metal coupler above it. However I tried removing it with a plier, no luck.
It is locked tight. I tried for 2 hours and ended up stripping the metal.
This is the part I need to replace but it's not coming off. I tried WD40 and
still no luck.

When I looked closer I am not sure this is a coupler. May be it's a vaccum
breaker? I am not sure. When I have no hose connected at all and turn it on
it still jets everywhere so I don't think it's back pressure. How can I get
this thing off and replace it?

By the way is this thing a spigot or a bibb?

Thanks!