I realize this is my third straight post...but just thought I'd address this real quick....

2. I know from therapy dog training that greyhounds are the only dogs NOT required to sit on command during the CGC/TDI test. I was told this is because retired racers are often never taught ti sit...they spend their lives laying or standing. I don't know know if this truely is the reason, but I have known 2 rescued greyhounds, recently off the track, that didn't know how to sit.
Our boy Prajna went through a cell dog program. He sits very well - and on command. I just went through CGC with Harmony and taught her to sit. Our old gals Star and Annie both sit on their own (we adopted them both as seniors so I don't know if they were taught to sit or not by previous owners). All this to say that greyhounds can and do sit. It tends to not be their favorite position (too hard to sleep while sitting...lol)

I think most owners just don't know how to train the gh to sit or don't want to take the time. And, honestly, its not that important in their day to day lives.