The session was challenging for me as one client was at a beginners level and the other more advanced. I charged them both my customary hourly fee. I understand that some trainers offer discounted prices for training 2 people together. Should I feel obligated to offer a “special rate” in order to keep these clients? I got the impression that they thought they would be getting a discounted rate.
you do not need to feel obligated to do anything. However, most trainers will charge a different rate when two clients train together within one hour of your time since you have more preparation work for two. That rate is often 50% above your hourly rate.
I am surprised, though, that you trained them together when you were caught off guard like that. I never had that happen to me but I am pretty sure that I would not have agreed to do so.