I'm with Ken...I''ve never had an invitation to the Captain's table and I really don't care if I ever get one. To me it would be one of those awkward events where you can't wait for it to be over. I'd prefer to be left alone, although I am not sure what I'll do if I ever do get invited. I'd hate to be rude.
The highest level person we've ever sat with was Pam Petcash when she was the CD on the Norway. She was assigned to our table. Everyone at our table was in a suite, but I am not sure if that was a factor or if it was just something Pam liked to do. She only showed up a couple times and then only to chat for a little while, and bolt down a salad and maybe an appetizer before she had to leave for some show or other event. But she was fun and our waiters took REALLY good care of us on every night. And when she was at the table they would show up with free wine for everyone.