postdated checks, teacher salaries--why is this even a question?

I went to a "teacher store" today to pick up some new borders (mine had too many staple holes to survive another year), and they had an enormous sign on their door:

All teachers can post-date checks to October 2nd--please just talk to manager
This sign made me stop, and then nod, and then sigh. I stopped because it seemed so bizarre to me that any business would do this; I nodded because if I had needed more than a few borders, I might have needed to do this; I sighed because, once again, teacher salaries were being acknowledged as too low--but only to the teachers themselves. Now, if I'd seen a similar sign at Starbucks--then I would have been impressed.

Whenever someone asks me why I got into teaching, I usually reply with something about loving kids, or enjoying my subject, or just loving what I do, but when I'm in a particularly foul mood (for example, after I've just finished grading 180 essays, or when I had to put my car repairs on a payment plan) I answer "Oh, you know, for the money." But teacher salaries should never be a joke. All discussions of "you only work nine months a year" aside (and, really, how is that true? Most teachers work all summer as well), teaching requires enormous amounts of energy, devotion, and education. For some reason, for all of the calls for greater teacher accountability, getting only "the best and the brightest," and highly qualified educators the idea of teacher-salaries are constantly left out of the equation. How does it feel to be constantly questioned, examined, and derided and never compensated? Maybe the feeling of ineffectiveness that is brought on by having to struggle to meet ends meet in the classroom and at home is one of the reasons that teacher turnover is so high.

It is hard to describe the frustration that teachers experience because of a lack of resources, a lack of time, and a lack of support. One of the ways that society communicates support is through pay. Why, then, is teacher pay even a question? How could anyone argue that you could pay teachers so little and expect so much? Where does the disconnect between "you're beyond valuable; you are responsible for so much, and we have to hold you to an high standard" and "well, we can't afford to pay that much, you understand" occur? How are teachers to convince their students that learning is important when it is constantly demonstrated that education isn't quite important enough to insure it gets what it needs?

How could it ever be okay that teachers have to post date checks to buy supplies they need for the school year? What message does that send about education?