Many locations have laws that require paychecks to show an hourly rate, even for salaried employees. What I was speaking of was more along the lines of how people talk about "teacher salaries" or "government employee salaries" vs. in reality being 'hourly employees' with an expected income (contingent upon being in paid status for every work day). I'm scheduled for a 37.5 hour work week. If I work 38 hours, I get paid an extra $12.50. If I work 37, I get paid $12.50 less (and get written up because I took time off without having enough leave time to cover it. We don't get unpaid leave time except for FMLA approved leave). I'm not salaried even though the public and media think I am. Versus teachers in my area who ARE salaried.... if they work 40 hours, they get paid $2000. If they work 60 hours (with hours before and after school hours, grading at home, etc...). They are still paid $2000.
Your example of teacher work days aren't what I'm talking about either. I'm talking about people who go in weeks early to start prepping their classrooms and lesson plans when they clearly know they are not going to be paid for that time and are not required to be there. You can say it's about being a good teacher and helping the kids all you want. But in reality, it's helping the kids at the expense of yourself.
In my opinion, it all boils down to this: If you want to be paid for those hours, you have to stop working them for free first. There is no leverage in negotiating if you just keep doing the same old thing and hoping they'll see it your way if you ask nicely.
I'm also hugely in favor of equalizing teacher salaries... the school district I grew up in is terrible, and teacher salaries start at $28k and max out at about $65k. I now live near one of the best in my state. Teachers there start at $48k and max out at over $110k. Of COURSE the best teachers want to work there, not my district. There's no incentive for them to go to low performing districts, but that doesn't help the kids in my hometown, and it doesn't help solve the inequality problem.
I don't buy the full union party-line... there are things I dislike about it. But I know that my job would be terrible (and a not worth doing) if it didn't have the protections that our unions afford. I knowingly and willingly take a lower pay rate than I'd get in the private sector for those protections and benefits, and I don't complain too much about it. But it also doesn't mean I won't lobby to get back the COLA raises and 2 sick days we gave up at our last contract negotiation during the recession so we didn't have to have lay-offs.