The answer to that depends entirely on the pack dynamics. If they are all generally happy to lay down and relax, then they can stay and even benefit from the calm energetic atmosphere that is often created during a session (many owners find themselves feeling very relaxed and sleep!). However, if you have a young dog or, by its character one that is likely to be bouncing around, inviting games from the dog I am working on or the owners, it would be best to have that dog in another room – as lovely as he/ her playfulness is, it could counteract the work I am doing during the session.