I think it really depends. It’s easy if you work for a corporate company, and you or your significant other can transfer to another location, or do something else in the company.
I think it’s fine, but you will have to deal with any reprocussions of your actions. If you break up, you must think about how this will affect the rest of your career, and the career of your SO.
I dated an instructor at my college. I was a teaching assistant for the class he taught. At the time, I saw nothing wrong with this. In fact, if it hadn’t been for our 13 year age difference, I don’t see why our relationship couldn’t have continued, especially after the class ended.