In my experience, some interviewers, particularly Amazon interviewers, get really anal about putting correct code on a whiteboard, sheet of paper, or bare text document. I personally do not when giving interviews.
My bigger problem, and I seem to depart from the vocal majority on this, is that my preferred normal workflow does not use whiteboards for anything besides task lists and diagrams. In 13 years[1] as an engineer I have never written actual or pseudocode on a whiteboard outside of an interview. I rarely do it on paper. I have never worked with anyone who did this very much, either.
[1] Granted, four of those were as an EE, but I still had to deal with code from time to time