I guess there are different theories about what our job is . . . I think of myself as a part of an Artistic Team, as well as the production team, regardless of my being a resident SM or just a hired gun - I am hired by the producer to mount a production and get it open on opening night. If, for any reason, there is something that might prevent that issue, I feel like it would be sort of negligent on my part not to bring it to the producers light. And this can be for what ever reason - director's incompetence, not enough production support, etc, etc. Who I talk depends on the situation, and based upon your experience.
I think a lot of this has to do with you experience level and comfort level. I mean, you have to sort of know what an extreme situation is and when you should raise a red flag.
At some point, they are going to trust me to maintain the show artistically, so why not should I have an artistic opinion about the product I am working on?
NOW . . . again, I am a staff member of a large regional theatre, head of my department, and report not only to the production manager, but to the artistic director. I know my situation is not a typical SM. As far as experience, I just pasy my 20 year mark in the business. (Sigh, I am old)