Really depends, I think.
If they were relatively 'normal' looking, then probably not. But if it was some mutilated body, then I'm not sure.
I have no work to take a day off from. Come all dead bodies, I have nothing to fear!
Hmmmm, is it a female body and is the body still warm?
Personally, I would take the day off. Between the shock of the discovery, and the questioning process that law enforcement would conduct on me probably being exhausting, I could make a decent case for a day off. But whether I would truly NEED a day off or not? I'm not sure.
Hmm, I've read a couple of criminal books lately so when you write 'found a body', I imagine a body of someone who died in some very unnatural conditions, all covered with blood, showing signs of some unbelievable violence and with some parts missing. So I think finding such a body would be quite shocking and I might not be able to go to work then.
But when you find a body, aren't you supposed to do something about it, call the police and tell them about the circumstances in which you found it? Wouldn't it take enough time to make you skip a work day anyway?
I guess if it was something that was emotionally detrimental to me, I'd cancel my lessons - more for the sake of my clients. It's a waste of their money if they get a lesson from me when I'm not 100%. This is similar to why I don't teach before 11am - I'm a night owl, and I'm not 100% in the morning. Also why my students prefer if we cancel a lesson when either they are or I am sick.
If I showed up to teach and was visibly unfocused and upset, the lesson would be less than it's worth. I guess this really depends on the kind of work someone does, but in some fields, it's shocking that bosses still want people to show up while sick or during a really bad time when the person can't give 100% for what they're being paid.