You mean mod responsibility, with no mod powers? Heck no. If I had to take that pressure, with no power in return, I would probably quit PC.
But if I got mod powers, then sure. I'm always on PC anyways, and I'm sure that I already have a couple of the pressures of being a mod.
Just a few of those pressures:
People always hating you for being responsible once in a while, or things just as simple as asking to play nice. People hating you for your own opinions("You're supposed to moderate, not have an opinion!"). Or if you say something slightly out of line, people automatically brand you as a stupid liar that doesn't deserve to be a mod. And the pressure of setting an example. Who wants that torture? It sounds pretty easy, but I'm sure that it's hard.