Oh - Logan would sit just fine next to a friend. That's why it was hard to practice. It was all the ~new~ dogs at shows he wanted to make adventure of. And I could neither practice nor discipline him there.
I don't know what Shell would do with strange dogs - although she meets a lot of them at hunt tests and of course I can discipline her on the line - probably she would puppy bow and want to play rather than try to mount them - she's more likely to throw herself at another dog's feet and smile. (Of course that'll get her DQ'ed too!)