The overtime topic is one that comes up ALL the time with Stage Managers. Some believe you never put in for it without risking the opportunity of ever working at a theatre again, and some believe it's 'part of the job' and the reason we get extra pay. Some believe you put in for it if you work it, and be damned if they don't want to hire you again. Much of it depends on how they treat you otherwise, I suppose, but if you notify the management in advance that a certain schedule will put you in an overtime situation, and they say 'ok', then they have no right to bitch about what it costs after the fact. That won't stop them, of course....
There will always be a debate about what duties are part of out job that we just have to do as part of our preparation for a show, and much of this discussion involves paperwork. If you're not specifically asked to prepare something by a certain time by management, then much of what we do is going to be considered, by them, to be on our own time. Yet we know it has to be done for the production to run smoothly and efficiently, and in those cases, I don't ask for OT. As a matter of fact, I rarely ask for OT except in a rehearsal situation where any actors go into OT, but that's just me. I know the extra work I do will help keep me in control, and reduce problems down the road, and I like that, so I think of it as part of my job. IF IT BENEFITS THE PRODUCTION and makes it all better, it's my job. Of course, there are limits to this... and drawing the line is a case by case situation.
Now, back to the main theme of your original post. If someone is treating you badly, you can certainly vent... but remember that what comes around, goes around, and the producer you may want to kill today may have the idela job open tomorrow, so it's always best to limit your circle of venting a little bit. Other SM's are great to vent to, but keep options open....