Many years ago I went to a salon where people specialized in a particular service- some only colored hair, some only cut, some did make up, trainees washed hair. There were different categories of people for hair cuts or coloring; it was a teaching salon, so you booked with a particular person but a master stylist charged more than a newer stylist, same with colorists. I hated that I couldn’t ever seem to get a cut & color appointment on the same day and had to come back for separate appointments.
All that to say is that there are salons that have junior employees who wash you & prep you for the stylist so the stylist can see more people (and make more $ at the end of the day). If you don’t like it, ask about it. It may be the direction your salon is going, or it might just be your stylist was super busy and someone was just trying to help her out.