Well first of all I liked what gafftaper said and second of all even during tech rehearsals in high school our 'Drama' teacher (who did teach English before but had lots of
theatre experience and the person who helped open me to the world of theatre) actually was never present in the booth with me or the sound person. Partially because it was 3 flights of stairs up and she had injured her leg the previous summer, but most of all she trusted tech. She had more problem with the actors which is why she stayed in the
house. Gafftaper was right about techies having a passion about what we do, and I know that if my old director in high school had a problem with lights during a rehearsal she'd tell me, and by the next rehearsal it would be fixed.
Now in college running lights, having my lighting/sound professor in the booth with us was a little nerve racking during rehearsals, but when it came to shows he would stay for about the first 5-10 minutes in case of troubleshooting and then he would leave because it was now our show.
I'm not sure if this helps any but I wanted to put in my 2 cents.