I am willing to bet that they won't be asked back to direct again and your future worries will be solved.
Next time, try to address this earlier in the rehearsal process or speak with the artistic director so that a "bad tech" can be avoided. This sounds to be like you waited too long and now the problem is out of your hands.
First, I disagree that a director giving notes during tech would constitute not having them back to direct again with a company. As many have pointed out already, things change during tech, and though one style of note giving may be preferable to another, that's not something that a company would blacklist a director for, nor should it be--at least in my experience.
Second, I disgree with the the statement regarding the SM's implied responsibility to discuss tech etiquitte with the director in the rehearsal process, or to go to the artistic director with the concerns. I don't think it's something that the SM needs to get involved in. If the director likes to give notes during tech, it's ok. It may not be a style you're used to, but it happens all over, believe me. Unless it is completely throwing off an ENTIRE rehearsal, let the director work in the way they need. The tech will finish and all will be well. Part of our job is to be flexible (within the limitations of the given company) and adapt to different people and their ways of working. As long as we follow any company given rules, and everyone is being treated with respect, then it's fine.
I don't think you've waited too long for anything. I think you're in a new tech situation that you may not have experienced before. Buckle up and enjoy the ride, and do whatever you can to keep the ride moving forwards. That's all you can do.
We are not in charge of situations, just responsible for them (I stole that quote from someone--sorry that I don't give credit because I can't remember who it's from)
