I can understand the logic somewhat behind not allowing teachers to do certain kinds of modeling on the side (like underwear, nude, swimsuit, etc etc). Not saying I agree with it or anything, but the idea behind firing teachers for doing things like that is similar to stories I've heard of people getting fired in other jobs. It has nothing to do with the quality of education of students or anything; rather, I'd assume it has to do simply with the reputation of the school. People don't care that a teacher is attractive, but if parents have the possibility of finding pictures of scantily clad teachers, they'll likely throw a fit. School boards/principals/etc don't want to deal with the possibility of that kind of controversy, I'd imagine. I'd be interested in seeing comparisons of these kinds of issues in other countries though.

It kind of makes me think of something a saw where a high ranking guy was fired from his company because he posted a video of himself going through the drive through of a Chik-fil-a and harassing the lady at the window because he disagree with the company's stance on marriage. Doesn't really effect his performance on his job, and it's his own personal viewpoint, but it can create a negative image for his company.

I think in general what people do outside of work should be their own business as long as they are being productive at work and bringing no harm to the other employees/students/etc, whether you agree with what they are doing outside of work or not. I guess you could still see these things as harming the image of the school or company though, which I think makes it seem to be a little more in a gray area.