People who are on the make.
If they are both over 18 and hopefully single, then who cares if, over the course of the dance training, they develop “deeper feelings” and by mutual choice want to be together.
Are you aware of the issues that develop when people who hold authority have relationships with (students) under their authority?
When I was growing up there were several strict Calvinistic churches in my neighborhood that basically considered “pre-marital dancing” among the worst of sins. That puritanical influence still holds for some.
As for me, I think “informing” your spouse is necessary and appropriate since practicing and performing will require a certain time commitment. “Permission” isn’t needed, but being up front about where you are and what you are doing is good form. To me dancing isn’t going to make you cheat, unless you were inclined to do so anyway.
Personally, if I were married, I wouldn’t want to dance with anyone but my husband (and even though I am not married, I would still not want to dance with a random guy), and would politely refuse, if asked. I don’t consider it “the worst of sins” or anything like that, but for me it’s something that I reserve for my significant other, just like things like holding hands, etc.
Since shared world view is important to me, I would want to be with a guy who felt the same way.
My husband likes to dance more than I do. I would encourage him to participate and I would gladly cheer him on. I really don’t get the fuss. I wish there had been a video to accompany the updated article.
This is just a foreign worldview to me. To each his/her own. A few days ago, I went to a bar with some classmates and professors after our night class to celebrate my admission and of course danced with them and others. There was nothing sexual about it. It was having fun and celebrating with friends.
My partner knew because I texted him before I went that I was heading to a bar. To us, this works. I’d assume that this (the dancing) works with the profs, students, etc. 
Exactly - I think everyone is different. To me, it’s not that it’s sexual. It’s like holding hands or hugging - it’s not sexual, but it’s something I reserve for just a few people in my life. Nothing wrong with others feeling differently about it.