I don't wear at work. I think if you're not incontinent, diapers, like other fetish type objects, need to stay at home. There is just no good reason to wear to work. While you can't be fired for it, presumably if your boss/senior management noticed you were only wearing them certain days they'd know it wasn't because you needed them (assuming you don't work in an area where you can't take bathroom breaks). And I would think that could affect, maybe unconsciously on your boss' part, whether you got a promotion, got laid off if there were budget cuts, etc. Maybe it's just where I work, but there are people who fit in (and suck up), and there are people who just don't, and the ones who don't fit in/suck up tend to be the ones who don't last long, or miss out on promotions over other less qualified people. So, I'm not going to do anything to get me noticed in a negative way.
Also, if I wore to work I'd probably be less social, as others said, and less likely to want to speak out at a meeting or do anything else to draw attention to myself.
So yeah, there is very little chance I'd ever wear to work.