If I pay money to attend a seminar, it's because I feel the seminar instructor is worth the money. I don't like my seminar time dominated by someone else trying to peddle their aikido. I look for a partner who can help me figure out what the instructor demonstrates. As a partner, I view my job is to help my partner figure out what the instructor demonstrates.
I'm attending a three days seminar with Suganuma Sensei (8th dan) starting tomorrow, and this is the mind frame I'm going to try to adopt for it, thank you!
Regarding the main post: Since I'm just a 4th kyu and train in a mostly black belts group, I feel like I have a black belt in dealing with such behaviors. I'm a little depressed to hear that this is not something that goes away with time.